I am surprised Firaxis didn't work on an X-Com 3. I would guess the fan base is still huge.
I'm getting old and I don't play videogames anymore, but if I have a month of free time imprisoned in a cell with nothing else to do, I'd give xcom2 with LwotC a go. (and Master of Magic, and Master of Orion 2, etc).
[0]: https://www.ufopaedia.org/index.php/Long_War_of_the_Chosen