how to enable wallet in a confirmed node
Yes, that is a wallet feature. You would have to recompile without the --disable-wallet flag, starting back at executing the autotools configure script: ./configure. See https://github.com/bitcoin/bitcoin/blob/master/doc/build-unix.md#disable-wallet-mode.

You also have to make sure you don't set the -disablewallet flag when you run bitcoind or have it in your bitcoin.conf file.

If you need to recompile, you could still back up the data in the .bitcoin folder, which includes the blockchain and UTXO set and copy it back over when the installation is complete. That way you don't have to download the blockchain again.