Did you double-check the bitcoin address from electrum where you send your bitcoin from bitcoin core?

Maybe you put a wrong bitcoin address that is why no pending transaction or confirmed transaction in your electrum wallet.

Since you said your electrum wallet is connected to 3 nodes it means that your wallet is running fine.

There are 2 possibilities maybe you put a wrong bitcoin address or you use a fake electrum wallet.

Can you clarify if where did you download the electrum wallet and put the bitcoin address you use for receiving bitcoin from bitcoin core here, so that we can find what actually the reason for not showing transaction in your electrum history and let me know if what version of electrum wallet you use?