If you didn't get one of the few TPM modules available yesterday, don't worry—you almost certainly don't need one. OEM hardware TPM is generally considered the most hardened version, and it's soldered directly to the board in PCs intended for enterprise use. Less-hardened
firmware TPM support is built right into modern AMD and Intel processors, and that will satisfy Windows 11's TPM requirement just fine.
It's a bit difficult to get a complete, accurate list of all CPUs with support for onboard, firmware-based TPM, largely because the demand for it was fairly low until this week. As far as we can see, every x86_64 CPU on Microsoft's
supported processor lists includes that support.