Looking for something easy to learn but gets deeper and more complex

I I just realised I’ve only played 3 games in the last 5 years (Football Manager, Farmville 2, and Red Dead Redemption 2).

When I was younger, I enjoyed Portal, Quake, Doom and Hitman Blood Money all on the XBox 360.

Have a bit more time in my hands now and looking for something that won’t take long to learn, but has real depth and complexity. Something I can really get into over the next few months. I’m open to any genre, something a bit unusual. I am not squeamish in the slightest and don’t mind something dark. But equally can do something light and fun, as long as its engaging.

Prefer something on Steam, Epic or PS4, and not a game on my phone (or i’ll never stop). Thanks!