The key to me was pulling it off the exchanges as they then own access to your assets. They shut down, you will be stuck fighting to get your crypto back. Airlocking it into my ledger keeps me in total control. I hadn't looked at "moving" wallets so I wasn't sure how that all worked.
As for my seed phrase, I keep two copies, one in a firebox and one locked away in my work office. I considered putting in my password manager (bitwarden if interested) but liked it only physically written on paper.