I used command
dumpprivkey bc1(recieve address I just generated)I tried importing into electrum with prefix but no luck either. Just like I explained in point 6 when you paste that private key into bitaddress.org (offline version from github) you get many addresses but none even looks like recieve address generated in bitcoin core (bc1.....)
Same situation happens when you generate address with native segwit Bech32 unchecked.
Can you try creating a new Bitcoin Core wallet, and then importing that private key into the new wallet using importprivkey, and see if the new wallet shows a different address?
Just did that on fresh linux virtual machine.
importprivatekey (...)
null
And nothing else happened.