Question about Lian-Li O11Dynamic XL

Vertical for sure. The CPU fan should not collide with the power cable of the GPU.

I can recommend the case for air cooling. For water, the case is too bad in my eyes as far as airflow is concerned. The radiators choke off the airflow too much. However, opinions differ on this point. For me, water above 35 degrees is no longer okay and a good airflow case almost always keeps water below 35 or even 30 degrees.

Lian-Li has specially built a small tool... It's best to check it out here:
https://lian-li.com/lian-li-pc...
O11DXL
Most models seem to fit without the Nvidia adapter cable... maybe you need a narrower adapter cable or an ATXv3 power supply.