Is there an easy way to get the signed raw transaction on bitcoin core, electrum wallet or any other popular wallets before or without broadcasting the transaction to the network?
Regarding Bitcoin Core you can do it using bitcoin-cli and
signrawtransactionwithkey or
signrawtransactionwithwallet commands.
The other way is to install Armory which adds GUI to Bitcoin Core. The expert mode of that GUI has the option to create and sign the raw transaction.