the fact thats your asking for iem makes me think you are running portable and moving around and doing stuff with your hands so bear that in mind with my reply aslo i assume you are comming from fixed cable (no connectors) comercial consumer mainstream available iems
I run 2 pairs of iems
w700i sony which was one of the first wireless ldac wearable neckbands (it's been upgraded now)
and my long term shure 215se which are wired with mmcx connectors.
I notice you didnt say wether you wanted wired or wireless and wether you should have ANC (noise canceling).
for durability I love my shure 215 that mmcx connector alows me to change the cable if it gets broken and retain the earphone also although it doesn't have anc I really love expandable foam (which can be ordered online when perished) if you currently rock a cheap pair iem order some third part foam to replace those rubber tips to see how you like them on your current iem it really makes a difference but some just hate the fit of the foam..NOTE shure use the term sound isolating this is not the same as noise canceling. the foam cuts out alot of noise but its not in any way active noise canceling ANC
Also shure launched
https://www.shure.com/en-US/products/earphones/aonic3 which are a new design been getting good reviews as of late.
I have had alot of iem's over the years durability of the wire is the single biggest problem, the next biggest problem is is how they secure to you (wired). I love that fact that shure hook over the ears it is much more reassuring fit especially with the foam. alot of iems use its easy to move around but with all wired iem there that risk you catch them and pull them out of the ear canal when wired to the device I am sure you know what i mean everybody has experienced this at some point.
Wireless (wired for best quality but wireless has its conviences but you will loose quality)
one route is neckband same problem with connection on cable to earphone unless its a mmcx connector. neckbands have limitations to say wireless earbuds but alot of earbuds don't hook over the ear I had a pair of bose wireless sports and I hated them they went with this fin in in ear design and I hated the fit and when they fell out they bounce all over the place. but with neckband there isn't really any weight to pull them out, and if you pull them to talk to someone they drop down a few inches and on the day to day stuff they are out the way the hand area and where you catch that wire for the dreaded canal pull, I actually like wearable neckbands in preference to wireless in ear earbuds with no hook over design and would advocate for it..
Iems sonically are not going to compete with a decent on ear or over ear design. unless someone can suggest me a mighty awesome pair. Also I would be very wary of spending that kinda of money on a fixed cable iems that in my case would be in and out of pockets all day. because once busted there done and iems do get alot of abuse for that reason.
So sonically I would deprioritize them and go with fit, maintaince and isolation vrs cost if you lose a wireless bud or break a cable.
Ps i have never replaced the shure cable on my 215 and that surprises me cause most iems I have trashed cables in usually less than a year.
here is whatfi 2021 list
https://www.whathifi.com/us/best-buys/best-in-ear-headphones-budget-and-premium
I have 1000mx4 over ear which and for anc its awesome so its probably amazing on the 1000 earbuds on the what hifi list. however I am not a fan of this shove in ear design.
Shure 215 425 and aonic 3 you can buy them with a truewireless hook over the ear battery receiver design I would gravitate towards this however it doesnt support ldac of aptx hd bt codecs. but it is a mmcx connector so thats a plus and you could get wire as a backup if it breaks or runs outa juice and you got a 3.5mm portible.
https://www.shure.com/en-US/products/accessories/rmce-tw1
Another way I have only recently discovered is to order mmcx neckband (single dac) with ldac or apt x hd. such as
https://www.amazon.com/FiiO-Neckband-Bluetooth-Earphone-Microphone/dp/B085DG6HXH and buy a decent set of mmcx earbuds from someone (shure arent the only company to make mmcx earphones) that way when the battery or cable gets messed up you can swap to the backup wire while you wait for a new band and keep the earbud drivers unlike so so so many iems designs which just need to get binned. If your looking for a 2 pin connection fitting neckband shanling mw200 although at the moment the price is higher than the fiio band
and if you need a external portable werable wireless dac (dual) which will improve sound seperation then this btr5 but be aware it is still transfering data wireless and as such you will loose quality via a wired dac. although that clip looks nasty and not something I want clipped at neck level. if its in a pocket with wired then it kinda like falling in to canal pull wire problem sooo meh in my case. but I can see advantages to it and more flexible options just not ergonomically as a clean solution, like most external dacs. Note the price at the moment is similar to the shanling mw200 but is quite a bit higher than the fiio band.
https://www.fiio.com/btr5
here is a descent list of removable iem earphones by type 2 pin or mmcx if your serious about spending big and want to do your own maintaince cable swap
https://soundgearlab.com/roundup/best-in-ear-monitors/
So lets say you did do a neckband well it kinda stays on your person all day whether you have earbuds in or out. putting it in and out of a bag just risks breakage. its still about the dimention arc size as a on-ear but definitely smaller. A few years back I got my first on-ear design which is not as big as a full over ear but sonically much better than iems. at the budget your outlining you could get a
mmcx wired iem and a on-ear (for compactness because I am still assuming you need that portability and are unwilling to move to a full over ear. I would make sure if can take a 3.5mm jack if wireless which i assume you would
however if you stay in a high crime inner city area I understand that iems can make you less of a target and thats something to consider. if not beat solo (at $300 you should consider full over ear sony 1000mx4 and bose 700) for anc and jbl live 400 (no anc but cheap if you want to try out on-ear) are being pushed buy rtings although I probably akg Y500 or N60 nc at about $150. I believe all these on-ears should provide something diffrent to the iems I would suggest both rather than a wireless $300 iem earbud for fear of loss or breakage. if you can go over ear then do so.
and for that genre of music I imagine dat phat bass...LOL is important thus i haven't suggested any open headphones for both commute and bass reasons, for clarity at home however with big bass fall off grado se80 on-ear, phillips shp 9500 over ear at budget end both wired around 100 dollars.and before spending big money on x2hr or BD dt880 or DT990 at $150-200 or more akg702 you need (25 olhm not 250 for portable devices version) senn HD660s . as open have a very different listening to closed I really wouldn't jump in big @ more than $200, remember these are all open and I not sure you want that big bass removed.
Sorry for the detailed portability durability and wearblitiy focused post but iems this is often more if the issue rather than sonically. I be gutted for you spending 200+ dollars on iems to get trashed and unusable within a year.
And for this reason I will never buy decent IEM without a 2 pin/mmcx connection again. NO more fixed wire options.
