What would YOU do to best protect this Bitcoin?
I would buy 2 ledger nano.
Recover the seed in electrum wallet (the old private keys) and send them instantly to my new wallets in ledger nano (10.5 btc to each). I would keep both seeds saved in a separate place.
The best is to buy a hardware wallet. Do no bothering making a offline wallet, offline computer and all that shit. Too many risks for a too high amount of money. Just pay a few USD in those HW wallet and let the professionals handle its security.
I would do the same although I wouldn't call offline computer risky. It's not hard to do when you have some experience with computers in general.
Using a hardware wallet is more noob friendly because they guyide you by the hend what to do and how.
Just to remind you that ransomware that encrypts files was found to be causing problems with hardware wallets by blocking your ability to access them on the compromised machine.