Any recommendations?
What is the preferred / required lifespan of the hardware? Keep in mind that iOS and Android devices have limited vendor support. For Android that's as little as 0 months from purchase (source: direct experience), though IIUC Google are targeting 3 years. If you buy used, you're well into that window. Apple's committment(s) are better.
Does this have to be mobile / battery powered? Or would a mains-powered, fixed-locations studio be sufficient / preferred?
If not, a small form-factor PC might suit this need (and could be a viable option for similar bare-iron segregation of workloads). You'll want a decent video chipset, though I doubt anything fancy is required. Look up Intel's NUC and similar units. There's a slight price premium for the small size, but lower-end systems are reasonable.
Given you're looking at Microsoft already, I'd suggest taking a look at Windows Surface as a mobile option. I've no experience with that myself.
There are apparently dedicated Zoom systems being sold and DIY'd, with budgets ranging from about $100 to $22k (!!!?)