Slapping a SSD onto the Raspberry Pi is like putting glitter on a pimple. For one, I don’t think there’s TRIM support for the SSD, and that will trash the SSD. Secondly, the SSD is way, way overkill for the capabilities of a RPi, so it’s really a wasteful decision. Do you have an actual issue to resolve, or it’s just that you now have the SATA interface available and have the itch to use it just because it’s there?

If the microSD performance is inadequate, perhaps more importantly you should ask yourself why would you stick with a Raspberry Pi to begin with. When the RPi was like 30$, it was simply unbeatable in performance over price. But with the prices exploding in the past few years, there are other SBCs with ARM processors that are within the same approximate cost with a RPi, but offering a lot more performance and benefits. For example, the Odroid N2+ has a CPU that significantly outperforms the one in RPi 4, faster RAM, better connectivity, faster display output, AND has a removable eMMC storage that’s significantly faster than a microSD.

Not sure if this FTP is still up, but here’s the link:

https://updateyodell.net/

If your Proxmox box has an Intel CPU with AMT, like the vPro series of CPUs, that’s basically a built-in BMC without a dedicated network interface. Once you configure it with the like of MeshCentral, you can remotely manage the Proxmox box, including full display replication.