I’d like to know if I connect my Trezor wallet to a MetaMask instance or if I import my seed phrase to another client I’ll be able to access my hidden wallet.
I’m talking about this: Passphrase ~ Hidden wallet.
The real question is: is the Trezor Suite the only possible way to access to my hidden wallets?
You can. Access is fully possible as long as other apps support the passphrase feature.
ledger also supports passphrases. In software wallets, I know that Mycelium can independently support setting a passphrase.
MM seems to only have the option to enter a passphrase when connecting to a hardware wallet.
the list of apps that support passphrase can be found here: Apps - Trezor Wiki
If passphrase in BIP39 standard, Why there are only few wallets support passphrase?(Trezor, Larger, Safepal)
there are many other wallets that support passphrase, see above