Hi guys, maybe it isn't the best section to ask this question but, there isn't one specific for this.

I tried Kaos on my laptop before the hdd breaks down and i found it a great distro, better than others more famous (i don't like very much the theme but, each to his own ), however, it lacks a lot of packages, so my question is: if i install kaos and then i switch to the Arch repos, there is compatibility?

Moved to pacman/package management section.

Not compatible at all, this is NOT an Arch based distribution, very different filesystem used, update schedule, naming, etc, please see:

And especially this part:

Understand the goal of KaOS, and what kind of user is targeted:

The repos are at a little over 1900 now, expect them to grow to a max of about 2100, you can request missing packages in the forum under "Feedback & Suggestions", explain why a package would be useful, what it adds that is not currently in the repos.

Plus you can always add missing packages yourself by building locally