You don't have to chain 8 PRs together, Github tries really hard to hide this from you but you can in fact review one commit at a time, which means you don't need to have a stack of 8 PRs that cascade into each other.
The funny thing about this debate for me is that i find it comes down to the committer. If the committer makes small commits in a stacked PR, where each commit is a logical unit of work, part of the "story" being told about the overall change, then i don't personally find it's that useful to stack them. The committer did the hard part, they wrote the story of changes in a logical, easy to parse manner.
If the story is a mess, where the commits are huge or out of logical order, etc - then it doesn't matter much in my view.. the PR(s) sucks either way.
I find stacked PRs to be a workflow solution to what to me is a UI problem.
Though I forget if you can even comment in the individual commits in that view. Complex multi-commit PRs have generally been a nightmare on GitHub in my experience.
When chaining commits it's possible to (for example) have a function that does THING and then have another PR that have a function that uses first one.
It's somewhat PITA when team has no-dead-code hard rule, but otherwise it's quite manageable and invites rich feedback. Reviewer and feedback can focus on atomic change (in example: function that does THING) and not on a grand picture.
But I also often use method of logical PRs and even written about it: https://xlii.space/eng/pr_trick/
If you, however, open a chain of 8 PRs, and merge them in the right order, the individual commits will be persisted in the git history. Potentially worth it if you like to have a "story" of several commits...