Mindustry is my go-to when I need to kill time offline. Cross compatible with pc android and iPhone on LAN I think, I haven't played multi-player in a long time. You could transfer save files as well. Originally a lite Factorio, last I played they added a new planet with different mechanics.

It does feel like there a a significant level of friction with each of these equivalent platforms though, including Lemmy. As with anything new it'll take time to catch on but each layer of complexity will be another stopping point for non-tech people.