a recovered_wallet.dat may or may not open with Bitcoin Core... theoretically, it should be compatible, so you should be able to open it directly... but it's possible that pywallet is not creating it in a format that Bitcoin Core can handle.

In which case, dumping the private keys out of it, then importing those into the wallet of your choice would be a viable solution.


Note that Electrum would enable you to import and scan the keys in a matter of minutes, whereas rescanning in Bitcoin Core could take hours. Neither guarantees that the "keys" found are actually going to contain any coins.