18 R1, 0NT4Y3 motherboard, TPM 2.0 module chip?

No - either the system has a TPM aboard or it doesn't, and if it doesn't, it cannot be added.

If the goal is Windows 11 support, even a TPM 2.0 won't help, as all the CPUs this system will take are five generations older than the oldest (8th) supported by Windows 11.

Thank you for your reply, maybe I have been miss informed as many viodes on youtube say you can buy a TMP chip since most mother boards seeme to have a conection spot.

As for the CPU there seems to be a way around this but the TPM is not bypassable.

There are desktop boards -- mostly in systems using retail mainboards from the big names (ASUS, MSI, etc) that support a TPM module being added.

Most pre-built desktops -- and essentially all notebooks -- do not.

There are ways (for now anyway) to bypass the TPM requirement -- but realize that Microsoft has publicly stated that it may update Windows 11 in the future to enforce the requirement.  Were that to happen,  you'd be stuck with a system that would be end of the road update wise. 

https://www.tomshardware.com/how-to/bypass-windows-11-tpm-requirement

Hello Allonzo

  I know this is an old post , I see you asked the question way back in 2021 ...But..I also have the 18" Alien from 2015 and I am running Windows 11 just fine and so can yours . I am sure you have moved on to something else by now..but I thought I would put this out there for anyone with the same question about the 18".