https://formdworks.com / https://www.reddit.com/r/FormD/
I have the old T1 v1.1 (slightly smaller at 9.5L) - my current build has a 4090 FE & 5800X3D in it, all air cooled with excellent temps.
There's a particular YouTuber who does a lot of reviewing of SFF cases: https://www.youtube.com/watch?v=dTwie1pxuro