This is my spin on Orange Pi 5 Case that is designed with 2280 SSD in mind and a 5015 radial fan for cooling. The piece of painters tape is used as a air duct to increase airflow above SOC. To mount fan I used countersunk m3x20 and nuts (barely fitted). For mounting feet I used m3 with cylindrical head that hide inside feet.
In my particular case I had to file away some material around USB and ethernet port, but rest was fine. Plus I left supports inside top part to keep it cleaner but still have an option to assemble it from the top
The tolerances around ports are tight so you can use horizontal expansion coefficient around -0.1...-0.2.
Might add another option, with different height so that gpio pins had more space