For me it’s first person puzzle games. I can think of maybe a dozen off the top of my head that came out in the last decade. I especially enjoy when they’re open world. The ability to just quit a puzzle that’s stumped you and go try something else for a little bit is incredibly refreshing.
The First Person Stealth Sim genre (Thief, Dishonored, etc) has been getting very little love in the last few years. Sadly the Arkane games don’t embrace it anymore; while great Prey was borderline as you really couldn’t control the stealth in many sections, and Deathloop and Red Rain are primarily short action games.
Have you played the two most recent deus ex games? HR is my personal favorite but I liked MD more for its atmosphere and level design. Both are primarily 1st person but switch to 3rd person when using cover.
I have, though even MD is getting on for 7 years old now. I don’t think that the series lived up to it’s roots in either title. I found myself feeling very constrained by them; I don’t necessarily mind if I have to play a character (Corvo is great as a Tabula Rasa) but Adam Jensen and his backstory are so fundamentally unlikeable.
Although they’re somewhat different the modern Hitman trilogy scratches this same itch for me (especially turning some of the guidance in the UI off and exploring the levels yourself, they’re actually designed well for that). Gloomwood is in early access but is shaping up really well and is inspired by classic Thief.