This has a name, it’s called CLS (cumulative layout shift) and Google actually penalizes SERP rankings for pages with bad CLS. More info on it on lighthouse.dev (if I recall the domain correctly).
Google is an annoying example! Especially on mobile the search bar shifts around between mainpage, search field edit-mode, and results page, but shifts only a half second after loading a static version. End up clicking into a blank new search page because the doodle jumps to right under your fingertip.
Rules for thee but not for me!
Google also abuses their power of controlling Gmail to do special tricks in their email campaigns which regular senders cannot do. Using these they force white backgrounds on users who have dark mode enabled (because their default auto dark mode CSS is absolutely awful and makes emails look like crap).
