Also, please tell me if this makes sense, if the Trezor firmware update messed it up, wouldn't restoring it to a different wallet (in Electrum, Exodus) show the funds if they were really there?
Correct.
I could run it again and do as you suggested
You could also try other standard derivation paths, such as m/44'/0'/0' and m/49'/0'/0' just in case your Trezor Suite
really did something weird.
Is this the only time you have tried to access the wallet? Have you tried to access it and been successful previously? And I take it you never tested your restore process prior to sending funds to the wallet in the first place?
How certain are you that your seed phrase is correct? There is no chance that you could have reset the Trezor or generated a second seed phrase at some point?
Yes, thank you for that suggestion. I'll try those different derivation paths since I've already set up BTCRecover.
Embarrassingly, yes this is the only time I'm accessing the wallet again after initially setting it up and transferring funds into it. I didn't feel the need to test a restore prior to transferring funds as the set up had to make me enter the recovery twice.
I'm 100% certain that it's the right seed. I've only used it that one time. I've only gone through the setup once, so I only ever generated one set of recovery seed, which I had written down on three sheets of paper.