How can I recover the state of my wallet.dat file after encryption?
This should be as simple as waiting until Bitcoin Core is fully synchronized with the network to detect subsequent transactions. This assumes that subsequent transactions will use change addresses generated in the normal way (BIP-32).
Obviously, to fully recover the correct state, you’ll need to encrypt wallet.dat using the same password and enter all the same labels/descriptions/etc. However, if you are only interested in regaining control of all your funds, this is not necessary.