Trying an old Trezor Suite is the most reasonable thing to do, so i’m sorry that it didn’t resolve your problem.
A thing you should try is manually add some other types of accounts, see e.g. here.
Yes, that won’t be possible on a Trezor One.
I could provide you with instructions to build a custom version 1.10.3 installable on your Trezor – it would appear as “unofficial firmware”. However, I believe that this would be pointless, because…
…that’s the opposite of what I said.
The derivation path to use is provided by Suite. Any firmware, past or future, can render any derivation path that the wallet software chooses. If there was a change to the derivation paths, this would be a Suite-side change.
In your case, it seems most likely that account detection has failed somehow and Suite is simply not looking in the place where your coins are.