There's a little story: So I bought myself a new GPU and PC case without any research...

Long story short, here is a bracket I made to fit ASUS ROG-STRIX-RTX2080S-A8G-GAMING GPU into PHANTEKS ENTHOO EVOLV SHIFT AIR case.

You will need 4x M3 nuts, 2x M3 square nuts, 4x M3x10 screws and 6,4mm spacer with 6-32 threads (like this one https://www.tme.eu/gb/details/keys8716/metal-spacers/keystone/8716/)

Optionally, 173mm long M4 threaded rod + 2x M4 nuts and washer, 1,4x25mm nail.

The threaded rod and nails are meant to be used as reinforcement to the printed part, but although I used them, it was not much of an improvement.
Maybe hardened steel rod could be better, but I dont think it's necessary.

The rod should go through bottom of the part with nuts on both sides and washer on one side, the nails should go into two small holes under the spacer (Cut off the heads of the nails - I ended up using just one nail.)

With this bracket, there is no space for standard 120mm or 140mm fan on the upper front of the case. You need to replace it with slim fan like for example Prolimatech Ultra Sleek Vortex 14 (140mm) or Noctua NF-A12x15-PWM (120mm).
On the bottom of the case, you should be able to fit 30mm thick radiator.

I also ordered those https://www.ebay.com/itm/113927950129, to improve the clearances on the front fan and PSU.

At full load after 30mins, the GPU is around 60°C and fans around 50%.