hey bro sounds awesome i myself made 7 fps games (quality varies lol) but only singleplayer, but i could provide (for free) 3d assets, you can already download or just take a look at mysketchfab page
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furthermore i myself consider my 2d art stuff of even better quality compared to my 3d stuff....but well art is opinionbased, to show off my "skills" you may look at my games
i made all these games all bymyself mostly using my own sprites, but i'd support other creators of 2-d art and bought quite some sprites for whom i own the rites to use them in games.....(but i own even more 3d art i bought lol) and tools of course lol im addicted to collecting all dev-tools i stumble upon :)