hello guys I want to use apps apk as my own store to add more apk files to download on my phone. is that possible ?

The F-Droid client allows you to add custom repositories and also to disable the default repository (if so desired).

serpent You'd need to build the app yourself and direct the repository to your own. It's definitely possible and others have done it, but it may not be as easy as you think if you're not a developer or willing to do some work to get it up and running

Can anyone reccommend a developer that can help me with that ?

I don't know one and am not a developer just an average user who has read a lot of these posts but depending on your reason for wanting to do this I might suggest using Obtainium.

https://github.com/ImranR98/Obtainium

It pulls built apps or apks from GitHub so you don't have to build them and avoids fdroid 3rd party if that is a concern.. there seems to be plenty of people on GOS with different views on fdroid. Obtainium can pull built apps from most sources if you trust the source ie GitHub and cant or don't want to build your own apks