Segregating web and app activities with multiple PCs

I am in your shoes. I have a qubes laptop, mac, linux desktop, and windows pc. All are old, and the latter three are mostly treated as untrusted. Qubes-os is made for this. But It has two limitations relevant to this. Nested virtualization and gpu acceleration. There are ways around it in both, but this is where that other hardware your getting comes in. Do all you can in qubes, making vms as needed. This way, you only need to keep passwords in, and backup one machine. Then treat your other machine(s) as untrusted. For example, playing video games or copying code to them for testing. You can freely wipe and reinstall the untrusted machines. If you know configuration management, like ansible, you can manage them with that making wiping and repurposing easier. If one is for gaming, make a steam buying account with its own qube on your main laptop, to gift games to your steam playing account on your gaming desktop. Bazzite is a good os for this. Since Steam backs up all your games, you don’t even need to back it up. If you must run windows, install it with a local account only. Not a microsoft account. Theres a cat and mouse game going on here, so you’ll have to look up the current work around. Or maybe someone here can reply with it. You’ll want to back up your installer because the local account only workaround will probably change again by the time you re use it. Or make a dummy MS account for installation and never log into it after installation. So far, I’ve been able to not have an MS account, even though I made a dummy one and used it to log into minecraft. If one of these is a mac, you can turn on ssh and push to or backup all its files from qubes too. But its own time machine will be more efficient if those are large files.