For posterity, this was closed by feature/noverlay being merged: https://lists.gnu.org/archive/html/emacs-devel/2022-10/msg02166.html
- bug#35453: 26.1; Poor performance of vertical-motion in lar... Ihor Radchenko
- bug#35453: 26.1; Poor performance of vertical-motion i... Eli Zaretskii
- bug#35453: 26.1; Poor performance of vertical-moti... Stefan Kangas