I know people get incredibly upset whenever this gets mentioned because suddenly they DO want it again but that was a big part of what “web components” were. When you need that level of isolation you can get it for free without any extra work.
Web Components are doing much more with isolation than just isolating styles.
You don't want/need to kill your a11y, form participation, and a bunch of other things (and laboriously solve them with Javascript) just because you want to scope your styles