Might be worth starting in c/RPG with basic questions, and if they end up drumming up a lot of conversation maybe a community is warranted? I know traveller has been around a long time, but I don't ever hear too much about it so I'd guess the community for it is pretty niche
It’s… weird. There seems to be a lot of people who play it, but you’re right: we don’t hear much about it.
There’s a Discord server (not a fan of Discord myself, I get lost easily) with tons of users (and many publishers) very much active. Even r/Traveller has decent traffic (but r/cepheusengine not so much). There’s a relatively active T5 community at MeWe as well.
Maybe most players are happy to use Discord. Aaaand maybe I should be asking over there if there would be people interested.
I’ll tell you, the RPG groups on lemmy tend to be very fantasy focused. It would be awesome to have a space for sci-fi. I’ll be glad to help you nurture it.