I admit I don't understand some of the problems mentioned in the article. E.g. that script that squashes the PR commits together - why would anyone need this,

I admit I don't understand some of the problems mentioned in the article. E.g. that script that squashes the PR commits together - why would anyone need this, what is wrong with diffing the PR branch and the target branch, using any tool you want? What forces you to look at the commit history? I'm perfectly fine with the git CLI and IntellJ for local review work, and Gitlab web UI for the communicative part of a code review. Only thing I agree with is, I (sometimes) hate the three-way unified diff in IntelliJ for merge/rebase conflicts. Other times (harmless conflicts), I love it over using the CLI. Personally, I found the example for the desired diff format confusing. I prefer split to unified diffs though.