Same. I also use paper tan right now and one bank account which i have to call if i want something (which i dont care much about, because its not ment to be accessed anyway) but yeah its just a question of time the bank does not send out TANs anymore.

My bank (or both of them) had no solution when i told them that i dont plan on having a phone number anymore. The one accepted it that they cant call me and send paper TANs, the other did not do paper tans for a few years now.

Btw: Your solution to store them sounds nice. Probably gonna adapt that