Sounds like you're on mych the same path as me... Mirlo was born out of the begions or enshittification at Bandcamp, they had a couple of different owners over the last couple of years and there's been layoffs. There's also Jam.Coop and Bandwagon.fm but I'm less familier with those but they all started around the same time and share similar ethos. I'm no expert with Castopod but happy to help if you have any basic questions. Once it's up and running I've found it really easy but there were a couple of daft things early on that I misunderstood, particularly the Fediverse handle part, basically you create a NEW Fediverse identity (I wasted lots of time wonderting why none of my existing Fedi handles didn't work). Oh and there's also an ajustment I had to make in the Config to allow files larger than 50mb, which was simple once I found the .php config but it wasn't obvious as I'm running on Yunohost here, basically meaning online guides diodn't match my set up. May sound utterly confusing to you... and it was to me but works a dream!