Why aren't more people talking about this? It been here at-least since the last two generation of CPUs from AMD (from my research worst offender) and Intel.

Likely because of this:

Microsoft Pluton is currently available on devices with AMD Ryzen® 6000, 7000, 8000, Ryzen AI and Qualcomm Snapdragon® 8cx Gen 3 and Snapdragon X series processors. Microsoft Pluton can be enabled on devices with Pluton capable processors running Windows 11, version 22H2 and later.

Emphasis mine. It's an optional function, and this sounds like it's targeted to businesses who either provide or have IT services. So like TPM, you can use it or not, and given the sharp rise in ransomware and other attacks, I can see why a business might want to use it.

How bad is it? I dunno. It seems to be so "noteworthy" that nobody is talking about it, and it sounds very optional.

Most Pluton devices on the market have it off my default and I am not aware of any device where you can't disable it (on x86).

From their description it seems like just another tpm - like chip with extra functionality. That "cloud to chip" stuff seems to be marketing bs to me, possibly a tpm like chip that can only be used by Azure services? Doesn't seem to me that it overrides the os in any way, so Linux would probably just ignore it withou the right drivers.

Pluton is a weird thing. It's not dedicated HW designed or produced by Microsoft, it's more of a specification which requires something like TPM2 hardware on a given SOC.

Most vendors do not implement the pluton spec in their offerings.