Yes, they each work a bit differently, though. ChaChi is doing NIP-29 communities, where there can be multiple communities hosted on the same relay. Flotilla can also display those types of communities, but is focused on relay-based communities where the relay is dedicated to a single community.

On ChaChi, the NIP-29 communities appear as separate communities, with only one unified chat room. I don't see any way to have more than one chat for different topics. There are other tabs for posts, videos, images, and polls, but that is the only means of categorization.

On Flotilla, a community may have multiple separate chat rooms for different sub-topics. For instance, a group of local Bitcoiners I belong to has separate chats for general discussion, for upcoming meetups, for talking about Bitcoin/Nostr projects you are working on, and for Q&A about how Bitcoin or Nostr stuff works. That's not possible on ChaChi that I can see, unless you set up a separate group for each of those chats.

Indeed, the way Flotilla displays NIP-29 groups is by treating the relay they live on as the "space" or server, and each community as a separate room. This is because the "space" is really just the relay that the community lives on, and then each community on that relay is just treated as a separate room, which works since NIP-29 communities only have one chat room per community. Flotilla does not appear to support displaying each NIP-29 communities posts, videos, images, or polls feeds.