Looks like the Pixel Tablet has 3 years of OS updates and 5 of security.

https://support.google.com/googlepixeltablet/answer/13555449?hl=en&ref_topic=13075701&sjid=2970932514574952490-NC#zippy=%2Cwhats-the-os-update-policy-for-the-pixel-tablet

On 13th Gen the Intel ME is disabled and 12th Gen are being updated to disable it as well. The AMD PSP is a different thing since there isn’t coreboot for AMD systems.