Thanks. These are really helpful. I am still thinking about my options here. May need a few days or even a few weeks to think about them and finally make a choice.
I don't think you have to take too much time for consideration.
Electrum is an open-source non custodial wallet.
Blockchain.com (formerly as blockchain.info) wallet is a close-source non custodial wallet.
Between an open-source and a close-source, your choice must be clear and very easy, it goes to open-source.
You can import private key to Electrum, then move your bitcoin to another new wallet that is created by Electrum wallet too.
Back up your new Electrum wallet too.
How to back up a seed phrase?