Fully agree with a twist - ban dumb large PRs.
To add to my openspec shilling above, I've been known to "fix" large PRs by reverse engineering specs from them and building each spec out in a separate PR.
Last week me and a coworker turned a 15k line PR into 10 x 1.5k line ones that went in smoothly.
Yes I do like to make a big pr first sometimes then it's usually pretty easy to split it into small ones and it's a helpful process in many ways. You can even present both together so people can see it either way, but I think in most systems it's better to have smaller prs merged one at a time.
For a rewrite, I guess sometimes it's better to have a spec then write to that, and PRs might be larger.