Game works fine inside editor but takes forever to load after build.

My game works just fine with reasonable loading times in the editor but after build when I run .exe right when it's going to load the very first game scene it takes +10 mins to load, but when eventually it loads the first scene everything starts to work just fine and loading times are back to normal. I've already messed around with API settings (Changed Directx11 to 12 (Experimental) or OpenGL), also tried changing compression method from default to LZ4. I also changed editor version from 2020.1.6f1 to 2020.2.7f1 and still the issue persists. Bear in mind that the project size is about 24 GBs and after build the game size is about 7 GBs. I notice a lot of "D3D shader create error for vertex shader [0x80070057]" appear in Player.log file after every failed start attempt. Two errors also show up at the end of build in the console tab (also shader related). I've been working on this project for 7 months now, any help would mean a lot to me. Thank you in advance.