If it's just for calls, look at DECT headphones. I have a Jabra model, don't know if they still make them.

Coverage is great, I can walk around my parents' house, and even out in the garden, without loss of signal. They live in a hundred-year-old stone house.

Sound quality is great for calls. Music is ok-ish. They don't have any kind of ANC.

Another drawback is the big-ass base that for some reason requires a dedicated power cord.

Thanks for that, I am looking at POTS audio interfaces and POTS simulators. Looks like with DACT I can do what I want cheaper than using multiple body packs.

For phone calls, Plantronics CS55 has worked great for me for over a decade. (Range not be as long as you need though)

If you're looking into bodypack, why not just carry the phone around? Spotty Wi-Fi / 4G coverage?

This is for calls where dial in is not permitted.

Are you not allowed to use Teams / Zoom / whatever on the phone? I used to do this before I had wireless headphones.

And to support what sibling said, I open the Teams app on my phone, not dial in, join the meeting and go walk the dog around the neighborhood. Unless you simply don’t have a smartphone (or an app for your meeting software), I can’t see how one would more simply solve your problem.