I built personal webpages in the 1990s, and still do it now, I included javascript then, and still do now - to make calculations, show interactive graphics, quantitative stuff about climate change - see for example this model.
I get your concept, that more websites should be written and hosted by individuals not big tech - but javascript is not the essence of the problem - js is just calculating stuff client-side for efficiency. In theory big tech could still serve up personalised algorithm-driven feeds and targeted advertising, just with server-side page generation (like php) and a few cookies, would waste more bandwidth but no stress to them. Whereas disabling client side calculations would kill what i do, as I can’t as an individual afford to host big calculations on cloud servers (which is also technically harder).