You can read each individual commit and review the PR as a whole. This is the way many people design and review PRs.

You don’t need to merge those changes progressively. If you do, you go through exactly the same process of creating a separate branch and PR. The only difference is that GH has now added some UI and automation for rebasing and merging the PRs. In the past we would have explained the chaining in the PR and rebased manually.

You don’t need CI to run on each commit.

You only lose your commit history if you squash merge, many people don’t, and you don’t have to either.

The arguments come from angle that doesn’t appear to be aware that stacked PRs were a thing before GH made these UX improvements.