I've worked in the project in my free time for a couple of months - give or take. I got the weapon and character model assets from this Unity Asset Store package: https://assetstore.unity.com/packages/3d/characters/toon-soldiers-ww2-edition-56...
The same package is in use in other games as well from what I've seen in YouTube. Search for Brass Brigade if you're interested.
Edit: I'm in no affiliation with Brass Brigade. I just felt it's worth mentioning