Txt files in an encrypted folder on multiple SD cards.

I wouldn't do a safe. I certainly wouldn't leave it in a drawer either. With a card you can bury the file in a mountain of others, tape them in obscure places, hide them creatively, split the keys between different cards.

No doubt certain cards will fail over a long period of time so you want multiple redundancy. And you only want to create them and open them on a machine that's never seen the internet.

If I did only have paper I wouldn't want it where I lived. These days safe deposit boxes are really hard to find so I'd prefer something I can create myself that's easily hidden.