On call shouldn't have 24/7 responsibilities. For example, I'm on call and took a call this morning due to MySQL Server running out of space. Terraform change later, it's no longer out of space and I'm back to my day. I'll take 30 minutes it took me to resolve out of my normal time elsewhere.

If on call balloons your 40 hours to 70 hours, yes, you have an issue. That's not normal and you should consider changing jobs.