Tor over Tor?
that’s explicitly blocked by the network as it’s a fairly easy vector for a denial of service (connect to tor through tor through tor through tor… and everything you do cost N time more than it should).
Whonix provides the kind of isolation you seems to be seeking. You can try to use that, or to look at how they made it work. I think it’s about configuring TorBrowser so it uses the tor outside the VM, and not the tor it bundles.