Oh SEMrush… some of the alerts/errors they display might not be as critical as they make you think.
With that being said, I’m not sure if there is much you can do as HubSpot doesn’t allow much customization for AMP versions. There is some interesting discussion here: https://community.hubspot.com/t5/HubSpot-Ideas/Google-AMP-Template/idi-p/312344
Maybe the best would be to just turn off AMP if your client is not getting much benefit from it. Also, AMP no longer seems to provide much of a benefit for most people, see: Google AMP is dead! AMP pages no longer get preferential treatment in Google search | Plausible Analytics