Ownership of Large PRs

I've been exploring how other teams handle large PRs. We generally push for breaking these PRs apart, but there will always be cases where they are slipping through. I notice that engineers can spend

I've been exploring how other teams handle large PRs. We generally push for breaking these PRs apart, but there will always be cases where they are slipping through. I notice that engineers can spend an hour or longer reviewing the changes to meet our quality standards or just giving up and approving. Our team has a general culture of pushing for deep ownership of the PR on the author to reduce the burden on other team members, but this isn't always possible with GitHub. Even if someone leaves comments across multiple files with explanations, it can be hard to track. How does everyone handle this? Are there tools we can use or processes that would make this easier? If there isn't already a tool, can you imagine one helping with this?