You still have a scenario where the encryption key is still on your physical device, LUKS with or without TPM, or … some kind of TPM based Linux encryption solution I have never heard of?
Does Windows Secure Boot work on Linux via the TPM?
No…
Am I missing something?
Theres no point in involving TPM in securing a linux computer.
In a scenario where you’ve physically lost your computer, using TPM or not it wont matter if your pc gets into the hands of someone who can attempt to brute force the keys.
If your pc is remotely compromised to the point it has something on it that can grab your keys, it also will not matter if you are using TPM in some way.
The only practical use of full disk encryption is if your linux pc and or laptop gets stolen and falls into the hands of a non tech savvy person, and in that scenario, going through the trouble of correctly binding LUKS to TPM will have just been a waste of time.
Thus, you should probably just use LUKS and not bother routing it through TPM.