I would check the dimensions on the 4090 you want to fit into the O11 Air Mini. I built my new mATX in the O11 Air Mini and it's a great case and pretty big for an mATX but it looks like you've got ~20mm clearance to put that card in. I'm not convinced the max clearance Lian Li report includes the two 140mm fans at the front of the case either. The cpu cooler clearance might be a little tight as well. Is there a reason you want to put it all in a small case? The O11 Dynamic EVO is a bit bigger and would seem to house it better.