>>8722432Katamari Damacy not exactly space game but like some Anons say in a previous thread fits her really well, Space Channel 5, Kerbal Space Program are all colorful games she might enjoy a lot. Mass Effect is popular and easy to get into, but there's also Outer Wilds that is great, Metroid series, Blaster Master, and maybe even Lego Star Wars that is amazing and could make a fun stream too.
There's a lot of great space games out there, she can easily go for popular titles on Steam and get some good streams out of it.