Probably because 0AD is one of the best around in its category. I may not have understood it fully however as it's too hard for me to play; I always get crushed

Probably because 0AD is one of the best around in its category. I may not have understood it fully however as it's too hard for me to play; I always get crushed by enemies before I can grow to a significant level. One of my favorites among FOSS RTS has been Glest, then Megaglest: https://megaglest.org/ https://megaglest.org/