Not just exit nodes, but guard and relay nodes as well. If they control all hops in the circuit, all your anonymity are belong to them.

You can increase the number of hops to make it very difficult. Guard nodes are pinned, so they might know who uses and who doesnt use Tor (doesnt matter if you arent using a bridge).

You can also set up your own exit/guard node and configure Tor accordingly. While not a recommended setup, it works pretty reliably.