

OpenTTD (Transport Tycoon)
Hedgewars (Worms)
Battle For Wesnoth (awesome turn-based game)
Shattered Pixel Dungeon (Rogue-like)
0A.D. (Age of Empires)
Frozen Bubble (Puzzle Bobble)
Pingus (Lemmings)
Mindustry (Factorio)
FreeOrion (Masters of Orion)
I totally get you but my rather elderly father loves 3D games - they’ve put hundreds of hours into Skyrim at this point haha. Could never get comfortable with keyboard and mouse but took to a gamepad incredibly quickly.
Sometimes a theme like fantasy or history can be the catalyst to give something the time and patience to learn it. My old man was a huge LOTR fan back in the day (the books especially) and thus the desire to play Skyrim was enough for him to suffer through learning a gamepad and analogue sticks.