Sharing my Left 4 Dead 2 realistic mod collection that can run without crashing on any custom campaigns using my bottleneck pc spec.. intel i34170, rx580 4gb, 8gb ddr3 1600mhz, 1tb WD blue hdd..
You can also use my settings and reshade settings shown, it will avoid crashing too.

Thanks to all the original creator of this mods..i included a list of all link from steam workshop in the download link

Mod Collection Download link: https://drive.google.com/drive/folder...
I will update download link if I made some change in the collection..

Realism Injector ReShade installation guide:    • Realism Injector ReShade installation...  

To fix the errors "missing particles" keep showing in the console
download this: https://drive.google.com/drive/folder...
and copy the folder named "particles" paste to this location: C:\Program Files (x86)\Steam\steamapps\common\Left 4 Dead 2\left4dead2