You might be better off looking for a community where the moderation optimizes for that kind of discussion (ex. Removing low effort comments, requiring citations, academic oriented, etc). It’s harder to find an entire instance that matches those points, but there should be a few communities like that
Then you can use the subscribed feed only, or block the communities you don’t like
For astronomy there is !astronomy@mander.xyz. The communities on mander.xyz are STEM focussed and usually well moderated.
You could also try
!astrophotography@lemmy.world
!space@mander.xyz
!space@lemmy.world
As for the instance, stay wherever you feel most comfortable. I have a few alts on other instances, including lemmy.world. You’re also free to move later if you decide to.
You can also check out the instance / communities at
https://feddit.uk/