It all depends upon what you do with it. I urged my kid to take a gap year after high school to study kid’s special interest with a master of it, abroad, because I was afraid that schools wouldn’t have started back up in-person. I was also afraid that the application round for admission for fall 2021 would be hypercompetitive, since so many people had taken gap years last year, and so was urging kid to apply not for fall 2021 and then defer, but apply for fall 2022. But kid pointed out that kid was afraid of losing academic momentum, was afraid that if they stepped off the treadmill, they’d never be able to get going again. I couldn’t blame them.
Other child said that the students who had taken gap years were clearly far more mature, far more self-confident than those who hadn’t.
If you know what you want to study, and are very eager to get started, then no gap year. If you’re totally burnt out, and have no idea what you want to do at school, then exploratory gap year. Plan it well. Maybe work/study in another country, becoming fluent in the language you studied in high school, doing work in a field that you might eventually be interested in studying. Try to do things that allow you to explore various interests, to find academic direction.