After the Coldcard incident, I'm thinking to change my setup to a 2/3 Multi Sign escheme.

I know that I need to back up all the seeds involved in it (3).

But, my questions are:
What's the best way to back up the descriptor?

And, how important is to register the multi sign on the hardware wallets ?

If I'm missing something, please add in the comments so everyone can do the back up properly.

Thanks!