Is there a way to make sure that the Bitcoin I have is stored on the Seed (+ Passphrase) that I had noted?
The only way I can figure it out is to recover the wallet using the Seed (+ Passphrase) that I had noted on a hardware wallet. If it shows funds on the Trezor suite, then Bitcoin is on the Seed (+ Passphrase) that I had made a note of.
Try to test your Recovery seed with a Dry Run recovery.
It’ll only test your seed, your Passphrase will be additional. There’s no way to test your Passphrase.
If the recovery seed stored in your device matches your recovery seed backup, you can be sure that funds are stored in the wallet backed by this recovery seed. Passphrase cannot be tested, but you actually test it every time you enter it. If you enter the correct passphrase (the one that backs up your wallet in combination with your recovery seed), you access the wallet with your funds. If you entered a different passphrase, you would access a completely different (empty) wallet.
On Model T, not at all, unless you count something like the risk of someone taking a picture of the seed via a camera in your room.
On Model One, not at all if you use the Advanced recovery feature.
With Standard recovery, you are entering individual words, in scrambled order, on your PC. This lowers the security somewhat:
with a 24-word seed, you are still safely inside the security margin
with less than 24 words, do not use Standard recovery. There are mitigations for possible attacks, but they are imperfect.