If I was stranded on an island for the rest of my life and could bring with me and play only three games, it would be these:
Morrowind (OpenMW), Jagged Alliance 2 (Stracciatella), OpenTTD
Wanna know why? Feel free to ask.

Steam Deck & Core i5-4690K, 16GB RAM, GeForce GTX 1650, Gentoo Linux