Could you specify your question a bit more,  I'm not sure I understand correctly.  Thank you.

I mean deleting all files when installing new packages maybe cause problems and deletion of user custom xcomp.

so cant aximmtery create default custom project folder that wont be deleted when install new packages ?

You are not only able to create your custom project folders, but it is heavily advised to do so.

Never save any of your content in the Common projects. We wrote about this here:
https://my.aximmetry.com/forum/postdetails/29-should-i-extend-common-libraries-with-my-o
Also never save back your own modifications of the stock studio sets to the same files.

If you stick to these rules, your xcomps will not be overwritten by the newer library versions.

Also your custom project should not be a single "default" folder. It is also advised to create a new project folder for each of your different TV shows.