I think it depends on the particular dev. I've known plenty (and I'm included in this group) for whom syntax highlighting is detrimental, not beneficial. I've also known many who find it very helpful.

I don't think there's a "one size fits all" here.

I was thinking that syntax highlighting is helpful when you start programming, because it helps you understand the structure of the code better, but with time the benefits fade.

i personally know only one developer (drh of SQLite fame) who does not like/use syntax highlighting. For most of us, it helps us quickly separate the noise from the code. Some brains don't need that, though, or they find it distracting. Like many around here, my intro to coding was back before syntax highlighting was a real thing, but i'd be loathe to go back to monochrome coding on a day-to-day basis.

To me it makes things easier to read, easier to spot mistakes. But I'm not full time developer. I'm just reading code.