Time Machine is already a separate 2 TB SSD that’s USB 3.something, since performance doesn’t matter at all there.
This drive would be primarily for storage of data I almost never consult, an APFS container for a nightly duplicate, and the VMs. It’s possible I’m overthinking the need for speed with the VMs, but there is also a sense that this is the drive where I’d dump the occasional huge file I encounter, so the higher performance of Thunderbolt might be welcome for more than just the VMs.
Doh! Got the wrong spec in head without checking—thanks! That does point toward a Thunderbolt 5-compatible drive, purely to have the max speed available should I want it.