Recently I found myself with a mini ITX motherboard and got a Ghost S1 case for it. The space saved and convenience of such a small factor is life changing. I’m never going back to ATX and big towers.
My Ryzen 5800X3D I think has issues with c states which caused reboots from low to high power states.
Thought it was the 3800RTX and 600w PSU. Upgrade SFX-l which has you loose the rear 120mm fan.
Whole thing really started to cook itself till I disabled the c state and switched back to the 600w
I do miss ATX because ITX boards generally do not have any expansion slots. Sure they come with Wifi, but if I decide to, say add a 2.5G(or 10G) network card, video capture or what have you, I'm out of luck.
I do not miss the case sizes. ATX are spacious, but TOO spacious, usually. Because the mainboard is large, most cases don't seem to optimize for space at all. So you fill the thing to the brim with all expansions you can think of and there's still a lot of wasted volume. Were I to go back to ATX, it would be with a non-orthodox case(open case, inside a desk, etc).