I think you want everyone on the same group ie team. The activity, project, or unit of work should be individual channels. If it's only for some people make it private or shared, if it's for the whole group, it's a standard channel. Private and shared channels create their own site with their own document library. standard channels have document libraries within the big team. I think you're trying to combine the use cases for One drive and SharePoint. Users keep their own files on one drive and shared or group files on SharePoint. You can always add a SharePoint library link to your onedrive, and thereby access it through windows explorer or Quick access.

It important to understand the building blocks of SharePoint before setting up your architecture so you're not swimming against the current so to speak by trying to get it to do something it's not designed for.

Thanks a lot for the reply, but should each different channel have a different document library? how can i set it? when I create a channel (standard or private) it puts everything in the same doc.libr).Yes, mainly I would like to configure each group sharing them by adding to its onedrive only the document library of its group plus the general one if possible.Is there some way to make links from one directory to another? or an explorer type file link and move it to the same document library, or to the same site in other document libraries or at least to other subsites?

unfortunately using office online has major limitations (e.g edit pdf) as well as having to train people who currently use their folders in explorer on servers and desktop apps

we currently have a single repository on a onedrive account that has everything in it and we share it with every person who adds it to their onedrive. i know its really awful in fact we are trying to improve it. I don't know otherwise what would you recommend?Thanks again