Even decently powerful phones can have issues with some of these.

Substack is particularly infuriating : sometimes it lags so badly that it takes seconds to display scrolled text (and bottom of text references stop working). And that's on a 2016 flagship : Samsung Galaxy S7 ! I shudder to think of the experience for slower phones...

(And Substack also manages to slow down to a glitchy crawl when there are a lot of (text only !) comments on my gaming desktop PC.)