I have 2 trezors and have tried accessing both of them with and without the passphrase and they both show empty wallets for my btc and eth. Since I am connected to my wallets through 3rd parties I can see that my eth still has all its tokens in them so for some reason SUite is accessing completely different wallets than it should be. For both eth and BTC.
How can I fix this or is there a third party wallet I can use to access my BTC like I can my eth?
From your description, it looks like you are accessing a different wallet. A different wallet can be accessed if you have a different recovery seed stored in your Trezor or if you use a different passphrase.
Generally, when the same recovery seed is used and the same passphrase is entered, the same wallet (with the same set of addresses) is accessed. There is no exception, the public-key cryptography ensures it generates always the same result.
There is a simple way how to verify you use the right recovery seed. Please check that the recovery seed stored in your Trezor device matches your recovery seed backup (the one you created when initialized your device for the first time). You can find instructions on how to perform this check here:
for Trezor Model One: https://trezor.io/learn/a/test-recovery-seed-on-trezor-model-one
for Trezor Model T: https://trezor.io/learn/a/test-recovery-seed-on-trezor-model-t
for Trezor Safe 3: https://trezor.io/learn/a/check-backup-on-trezor-safe-3
In case recovery seed in your device matches your recovery seed backup, the only way how to access a different wallet (with different addresses) is with a different passphrase.
The 3rd party wallet for BTC is for example Electrum. However, 3rd party wallet will not help you as you are accessing a different wallet (as mentioned above).
The reason why you see your ETH in the 3rd party wallet is that 3rd party wallets ofter create so called watch-only wallet after you pair it with Trezor for the first time. You are able to see the balance in this wallet, but you need the private key for the address that includes your funds if you want to manage these funds.
Simply put, you can see your ETH but you will not be able to send them out as you need a correct private key for it (which you do not have, that is why you cannot access desired wallet in Trezor Suite).