We are pretty much constantly adding features to communities (eg: @howo/changes-coming-to-a-community-near-you-). What would you like to see ?

"I also tried to ban people who are spamming my new community but it isn't working." => What do you mean ? If you set their roles to muted, their posts shouldn't appear.

Can we at least setup communities so people can't post in the comments if we do not want them to? => This actually exists ! It's called community type 2 or 3,

Type 2 allows anyone to comment but only members can posts, in type 3 only members can post or comment, see: @howo/communities-is-getting-an-update--what-to-expect