I’ve seen a lot of confusion online regarding Web development with Flutter and, often, it’s sadly for the wrong reasons. Specifically, people sometimes confuse it with the older Web-based mobile (and desktop) cross-platform frameworks, which basically were just Web pages running within browsers running within a wrapper app. That was truly cross-platform in the sense that the interfaces were the same anyway because you only had access to the interfaces normally accessible on the Web.

https://www.smashingmagazine.com/2020/06/common-cross-platform-issues-flutter/