AQtion on Steam
store.steampowered.com
Get ready for intense, skill-based FPS action with AQtion! Featuring the best of Action Quake 2, enjoy fast-paced combat, realistic weapons, and thrilling multiplayer battles. Dominate the arena now on Steam!

There is still a community around Action Quake2, mostly on discord, people still organize games: https://discord.aq2world.com

You can always play against bots or play local lan as well.