Question about the “passphrase” (25th word, etc. )

I understand that in Trezor wallets you can have “hidden” wallets. These are generated with your 24 seed phrase plus a passphrase you select.

My question is. How do you recover those hidden wallets if in the future (10/20 years) your Trezor model T doesn’t work anymore and by then the company that builds them is out of business?

In other words, I can download a software wallet and recover the wallet generated by the 24-word seed. How do I recover the other wallet(s) generated with those same 24-word seed plus a passphrase?