If you’ve got interest in deep simulation mechanics you can check out Cataclysm: Dark Days Ahead. It’s FOSS and, last I checked, still has an active developer community.
I know it’s a bit off topic, but is PlanetSide 2 approachable for new players still? I loved the original and tried the sequel when it came out but didn’t get much of a chance to play it. I’d be interested in giving it a shot
Depending on when you played the UI changed to be more mouse friendly. Still a game that is keyboard driven but it does have solid mouse based controls as well.