Well, the Fiio UTWS5 does not even support LDAC but aptX adaptive, will give you 53w into 16ohm, has an AK Dac chip, you can buy a 2pin version and then a 2pin to mmcx adapter to use all IEMs (or just the mmcx version if thats all u need)....
Of course, BT on paper performs less good compared to wired, you can check many of Amirs reviews and measurements on that over at audiosciencereviews, but I doubt you will hear the difference due to your use-case being on the go.
This setup is clearly made for on the go where outside noises are just a part of life, as long as you're not in a very quiet room you won't hear that already minuscule difference.
Let me tell you this: I own the UTWS3 and almost can't hear a difference. You know why? First reason being that modern codecs are almost completely transparent to me. But also: I mostly listen to music when working in the office or in the bus/train commuting to work or back home. Almost never am I at home all by myself in the quiet and actually critically listening to music to pay attention to fine details and small differences 100% fully committed to be concentrated just on that...
Wile working I actually need to think and solve problems, when I commute I also read stuff and hear the bus noises in the background. Again not fully concentrated to the music.
If I suddenly get distracted from work by the music due to some eargasm part of whatever, I just enjoy the moment and get back to work...
Now I dont believe that bitperfect playback is the holy grail... If you'd convert all of your flacs to max rate AAC I bet you wouldnt hear a difference, especially on the go...
And DACs do up/down-sample internally either way. My Aune T1 goes up to 24/96 so anything above will be downsampled, not even sure if by the DAC or by the software but it doesn't matter. Many times I test highres files through Adobe Audition to see the frequencies, and many times (but not always) you'll see that everything above the audible spectrum is just static noise, nothing that dynamically changes with the music as everything between 0hz-20khz.... so why would you need that for, just turn it into redbook and cut the crap above 20khz

With the RU2 Jriver will play 'bitperfect' by keeping the sampling rate but will turn 24bit to 32bit, is this considered not bitperfect? no information is removed by that... damn in one of the videos ill paste down a guy did a test playing the same sample and reducing bit by bit, from 16 all down to 4, I started hearing a difference at around 7-9 (noise)
I know I went off topic, and will share links that many may know and have already seen here on head-fi, and I certainly don't want to start a discussion on audio science & myths, but I recommend you checking out those:
(Check out the whole thing but especially the demos from 32m
https://www.xiph.org/video/vid2.shtml
https://web.archive.org/web/20200426202431/https://people.xiph.org/~xiphmont/demo/neil-young.html