We all hear (and continue to hear) that coaches love multi-sport athletes. But I came to the realization around 2019 that this is not entirely accurate. Coaches love players who are talented and athletic enough to be multi-sport athletes.
This doesn't mean that players shouldn't play other sports unless they're a 3-sport letter winner. But I think that encouraging players in the HS level to play other sports just to be a multi-sport athlete is not necessarily the right route.
Personal story
H played every sport imaginable up until the time he got serious about baseball, which would have been 8th grade. He just loved to compete, whether he was good at the sport or not.
Spring of 8th grade, he strongly considered playing football once he hit high school. But he ultimately came to the realization that he didn't enjoy football that much, and that he would only be playing in the hope that it would somehow help him in baseball. So he decided against it. Still, he felt like he needed to be that multi-sport athlete (see above), and wanted to find a way to do it.
He would ultimately swim for the HS team as a freshman because he DID enjoy it, and knew that it would be great conditioning for baseball (definitely was that). But it ultimately caused him a great deal of stress due to the season overlapping with the start of baseball. As a result, he's baseball only when it comes to his focus. But he still loves playing other sports on the side.