Welcome to the forum!
There is almost no difference between vanilla Arch and EndeavourOS. It’s mostly cosmetics, and some (very few) pre-configured settings and default packages. The most notable difference is that EndeavourOS adds a tiny custom repository with some helpful utilities, scripts, and theming. EndeavourOS intentionally stays very close to Arch – it is, for the most part, an easy way for newbies to start with Arch (by having a nice GUI installer and a handful of helpful utilities). To have a functioning system, you really don’t need any of that, it’s just something that most EndeavourOS users find convenient.
So, if you are using vanilla Arch, and are happy with it, there is, practically speaking, very little to gain if you decided to convert it to EndeavourOS.
The best part of EndeavourOS, and something that makes this distro truly unique and special, is this forum and the people on it. And if you are running vanilla Arch, you can fell right at home here, for the reasons I already stated.