Small world brother, small world...

(if you know you know).
I appreciate the thourough breakdown, thank you !
Now, fiddling with the dongle every single time you turn the console on to change the Aptx to "adaptive" sounds like a ball ache, aren't there any adapters that do that automatically ? (think I read something about it on Reddit).
Anyway thanks again man, appreciate it !
PS: which Ugreen adaptor did you get ? the USB C one or the other one that also comes with a microphone which plugs into controller ?
I know, a very small world indeed, right?
Yes, having to press that damn button every single time to turn on your PS5 is a real bummer. But here is a small tip: the BT adapter defaults to Aptx HD, as I said, and you have to press its button once to switch to Aptx AD, and the adapter will stay in that mode for as long as it keeps receiving power. That means that if you don't switch off your PS5, but use sleep mode instead, you can continue later exactly how you left it. PS5 has an option to keep supliying power to USB ports when in sleep mode, you want to use this one. So if you're one of those users that prefer use sleep mode anyways you won't be pressing that button very often I guess.
The adapter I use is the UGREEN that comes with the microphone for the Dualsense, exactly. Maybe there's a better way that my dumb ass couldn't figure out.
If that's still a deal breaker for you there are a few USB adapters that don't require pressing a button to switch modes. The
Avantree DG60P for instance has a physical switch to select the mode you want the adapter to use until you select the other. Problem solved.
In case this help I'll say that I really love my Momentum 4, seriously, there are awesome for everyday use. Sound quality is amazing, I like the app a lot and they're very comfortable to wear. I use them for many other things, while working, phone calls, walking my dog... and yes, a bit for gaming too, even though I'm not the kind of gamer that wear headphones all the time, but I think some games are meant to be played that way, like Silent Hill 2 Remake, which was the last game I played - several times using my Momentum 4. But I already had the Pulse 3D when I got the Momentum 4 and gaming wasn't my main use, that why I said that if you want them exclusively for gaming maybe you'll be better off getting a Pulse 3D or any other gaming headset if you don't own them already, since I can't hear much of a difference when gaming and the Pulse 3D are so easy to use and and has that seamless integration with PS5 user interface.
On the other hand if you're looking for a great pair of headphones you can use for music, phone call, sports... and gaming too, go ahead, the Momentum 4 are great for that price you mention and you won't regret buying them. I certainly don't, I'm very happy with them and I used them every single day. Oh, and that battery! I though the 60+ hours with ANC on advertised were a bit of an exaggeration but this thing never seems to run out of juice xD Here the difference between the Momentum 4 and the Pulse 3D is stark to say the least, its battery lasts 5x longer. If this helps I will say that ever since I got the Momentum 4 I've never used the Pulse 3D again. That must mean something.
Oh, and one last detail. The Momentum 4's USB is not only for charging the headsets, it's also an audio output, so you can plug them to your PC or any device equipped with an USB C port and enjoy a low latency audio experience (lag is only 39.6 ms). Some users report that audio quality using this method is superior to what they get via BT and even the jack 3.5mm input, but I haven't tested it to be honest. And even if I did I don't think I'll hear much of a difference.
I've tried using a Bluetooth dongle with my WH-1000XM5 and it was terrible. I don't think bluetooth headphones are meant for gaming.
Get an Audeze Maxwell or Sony's Pulse Elite, both works well for PS5 and PC, with on board equalizer.
It depends on the codec you're using. Since the XM5 doesn't support any low latency codec your only real option is to plug them directly to the Dualsense, which by the way also uses a low latency BT mode, but still BT, and as you can see people don't complain about the audio lag. Yes, it's a big higher than what get with the Pulse 3D (which is just 22 ms), but it adds just a few ms on top of that so the lag is still too low to notice. The difference between 20 and 40 ms is not really noticeable, the problem is most Headsets have around 300 ms over BT, and that doesn't feel great at all as you said.
If you use the right headphones and the right USB adapter the experience will be pretty similar to plugging them directly to the Dualsense, but it could be more convenient for some people since you don't need any cable at all. The catch being that both the headphones and the USB adapter have to support the same low latency codec, otherwise it won't work.
For instance, I also have a pair of SONY XM4 (which I already owned before I got my Momentum 4) and the only way I could get a decent gaming experience over BT was to plug them directly to the Dualsense. Using them with a BT adapter resulted in atrocious audio lag, even though I was using the same adapter I use now with the Momentum 4, but it was pointless since the XM4 don't support Aptx AD and using SBC causes a ton of lag (245 ms). The XM4 also support LDAC but lag is still crazy high (237 ms) and even if it was lower my adapter doesn't support that codec anyways.
Of course if you want the lowest amount of lag possible a gaming headset is still your best option, but some people just want a good pair of headphones for everyday use which they can use for gaming too, or maybe they already own a pair of headphones like the Momentum 4 and they'd like to use them for gaming instead of getting a gaming headset. In that case the combo headphones + BT adapter could be the best option. I mean, I definitely wouldn't walk my dog while wearing the Pulse 3D.

And for many reasons: audio quality for listening to music is far behind the quality you get from the Momentum 4, its esthetics show it's a gaming headset you don't want to use for things like walking or sports, they're way less conformable than the M4 and its battery doesn't even come close.