Eh, there’s something to be said for experimental periods in my view. Sometimes you try out new programs that you wouldn’t think would be useful but end up becoming essential. And then culling mercilessly anything that turns out to be not useful, or overly complex to maintain, reducing your maintenance burden.
It uses the Calibre database but isn’t a frontend per se. With care, you could share the db between the two, and just call up the desktop version when dedrm is needed. There’s also a docker mod with the LSIO container but I think it only supports format conversion.