Are there any open source team-based class shooters like tf2?

I want to start working with a game where players can choose a character/class and customize their loadout to suit their playstyle with that character across different maps and objectives, but something like that seems really hard to find. I'm fine if some of it isnt supported natively and requires a plugin(s) but I'd rather not use a nonOSS engine like the main suggestion I've seen here. I would use an existing engine, but 3D multiplayer on Unity/Unreal/etc isnt optimal for me.

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u/TalentTess — 7 days ago