What I like about @Start9 in comparison to Umbrel is the amazing support team that they have on Telegram. I honestly have not experienced better tech support from any other company. Their response time is very fast and that helped me a lot as I went down the self-sovereignty rabbit hole, coming from a non-technical background. I believe support for second HDD is in the timeline, but can't confirm 100%.

Start9 + Graphene would be a match made in heaven.