Full-disk encryption protects against anyone who steals your laptop. However, if someone can get access to your laptop without your knowledge, and you subsequently use the laptop, they could install a hardware or software mechanism to obtain your passphrase.
Yep. TXT or TPM can cryptographically verify boot integrity but aren't magic pixie dust for passphrase recovery via hardware tampering. In the end your adversary can just put in a hardware keylogger between the laptop keyboard and the motherboard.
