One of my teenage children is getting into Bitcoin, so bought them a Trezor safe 3, however the app wont load on their crappy laptop, leaving only my PC that i use with my Trezor/ Trezor Suite.
You can use Trezor Suite web version that needs no installation, and I think they also released mobile app but I didn't use it.
I read its possible to use multiple Trezor`s with Trezor Suite, however there`s no guide how to do this.
You can do the first thing I proposed above, that is the easy solution.
Another thing you can do is creating new login account on your computer, to keep everything separate, and than install Trezor Suite on fresh account.
Last option is installing small Linux OS on you children computer, it will be much faster and more useful.
If i plug in a new device does that info disappear replacing with the new device balance until i plug mine in again?
You can use multiple devices with same Trezor Suite app, but I think that you can't use them connected at the same time.
Nothing is going to disappear if you do that.
Is there a way to switch between both watch wallets while neither are plugged in.
Two devices will be visible, and you can eject, disconnect and hide them.
I would suggest keeping them separate if they are both the same model Trezor Safe 3., to avoid confusion.