In reply to TobyA:
The old LetsEncrypt root certificate expired in September 2021. If you're somehow running an old version of Chrome that uses the OS's certificate store, and that store hasn't been updated with the new root, then this might explain why you're seeing errors relating to certificate validity.
As far as I know, recent versions of Chrome use their own certificate store and should include the new LE root certificate. Have you tried uninstalling and re-installing Chrome?
UKC uses a Lets Encrypt site certificate that is valid from 3/12/2021 to 3/3/2022. If you right-click on the "Not Secure" element in the address bar, what does it tell you about the site certificate?
Edit: your hardware should be fine
Post edited at 12:23