I own a Mac Mini M4 myself, and although it's a solid box, I don't consider it a particularly good Docker platform. It's not that it's a bad Docker platform -- it's just not great.
Personally, I'd suggest selecting a recent generation i3, i5, i7 or i9 and install Proxmox on it (select something that has a decent number of cores/threads and at least 32GB of RAM). It'll change your world. There's very little you can't do with a Proxmox setup, as it's such a fabulous platform for the production and the experimental to live side-by-side.
I think for someone with your knowledge, and interest, Proxmox will allow you to explore whatever catches your fancy without having to worry about impacting your important everyday virtualizations. The key is to leave Proxmox itself as absolutely out-of-the-box as possible, and virtualize everything.
For the technically inclined, interested in something more server and Docker host oriented, it puts the Mac Mini (and MacOS for a server) to shame. More here:
