The TPM2 spec allows it to do much more than just hold private keys, it can act as a device identifier for attestation. If that's something you care about, then you might want to disable it.
The fact that Windows 11 won't work without a TPM is a bonus.
Secure Boot is part of UEFI. TPM2.0 is used only by bitlocker (at least for the average person, enterprises do store other keys in it).