Phone as cold wallet, seed stored on paper and USB. Am I good to go?

So, I am using an old iPhone without SIM for the 6 wallets I use, so I don‘t have them on my active phone. The old phone is SIM and PW secured and lies in a cupboard. My seeds are written down, laminated and put away. Currently thinking to put them in a house safe or bank safe. The seeds are additionally in a txt-file that is on an flash drive that will only see a connection to cleaned offline laptops.

I don‘t want a Trezor or Ledger, especially not the latter since they had some issues recently.

Any suggestions what I still could do better?

TIA!