WarGround

Yes. WarGround is free to play on Steam, so there is nothing to buy to start playing.

The minimum requirements for WarGround are: Windows 7, GeForce GTX 750, Intel Core i3, 8 GB RAM, 220 MB storage. It runs on Windows only. The recommended specs are in the System requirements section.

Yes. WarGround is multiplayer only. It supports online PvP.

Mostly, yes. Valve rates WarGround as Playable on the Steam Deck: it runs, but may need some manual setup.

Yes. WarGround is the full base game. You need nothing else to play it.