Good thinking with the RSS to let the artist choose.
Also cool with the upcoming addition for managing multiple artists.
My experience with Fountain is different. Not slow at all. However, I noticed that your artist page (on Fountain) has the same issue as I faced initially (the 500 error page). It seems to be a Wavlake/Fountain-related problem. I reached out to their support team, and they fixed it, but the issue reappeared shortly after. I contacted them again, and they were able to identify the real cause and make a permanent fix. You might want to reach out to them too, and feel free to mention my experience if it helps.
Good idea with the rebrand of the name. Sunami sounds more unique, catchy and positive. Love it.