I’m using mine with campfire andromedas most of the time. They are extremely resolving but I wouldn’t call them analytical - I love the sound. Sorta reminds me of the Beyer house sound without the overbrights and with more impactful bass. If you want more bass and more musical sound then the Vega is also amazing. I think for price the campfire IEMs blow away the competition that I’ve tried.
For over ears I haven’t used anything closed with the zx300 yet, but the four obvious suggestions would be: MrSpeakers Aeon Flow Closed, Beyer t5p (since you seem to like the Beyer sound), one of the closed Sonys, or the new Campfire Cascade. The AFC and the Cascade would be top of my list to try. Some people don’t think AFC is really portable, I guess it depends on your definition - I’m someone who’ll lug my Elears around in my bag sometimes though haha.
Worth noting with the Cascade (which is very, very new - see the thread about it) is that Ken from Campfire specifically recommended pairing it with the zx300, and it’s supposed to have a signature like the Vega which is a well loved, very musical but well resolving, headphone. Initially reviews are still coming out but it looks promising for a more bass heavy and musica alternative to the AFC.
Edit: wanted to add that you should save some budget for a balanced cable with any of the above. I don’t think any come with a balanced cable let alone a 4.4mm one and the zx300 is (more) glorious in balanced mode.