DropBox to SharePoint migration

I'm currently working on migrating a big company's data from DropBox to SharePoint and i can't quite decide on how to structure the whole SharePoint environment.

So as you may know DropBox has an admin section where you add your members, groups and content to share and it is pretty straightforward on how to implement simple things and by that, i mean that you get your members on some groups and then you share specific folders (from your content) to that group directly.

As of SharePoint now, i found out that it has more or less the same functionality but it really gets pretty inconvenient on how to implement this. I created a new site, then i created my groups and added some users to them, then i created as many document libraries as my shared folders were on DropBox, i stopped inheritance from the site and added groups directly to the document libraries. All that, took me quite a while, more than 8 hours, for 30 document libraries and 20 groups mostly due to the back and forth i had to go through settings, permissions, libraries etc.

Would it be, let's say, more practical or rather make more sense to create a new site for every shared folder i have on DropBox and add members directly from the site's homepage?

What would you do for such a case?

Thanks in advance

PS. The migration tool that SharePoint admin center provides it comes pretty handy and it works good, but transfers data quite slowly.

Solution

TLDR: Use sites, not libraries, for different user groups.

SharePoint makes the following things easy:

Sharing a whole site (by inviting people as members (edit) or visiors (read))
Sharing a single file (with a person that you don't want to have access to the other stuff on the site)

SharePoint makes the following very hard:

sharing specific libraries with distinct groups of people. This requires a lot of setup work and is a maintenance nightmare. You also need to be an administrator of the each site and know where in the depth of the SharePoint settings you can find the switch to break permissions and invite other people to a library.

It is not recommended practice to share libraries like that.

In your scenario, you would be served better with individual team sites using O365 groups. Then add members via the home page sharing button. The site should be the permission boundaries and these permissions should not be broken for any site content.

If the need arises to break permissions for certain content, it's time to move that content to a separate site with its own membership groups.

Using O365 groups, any site membership can then be viewed, managed and audited in the SharePoint admin portal and the M365 admin portal. No SharePoint knowledge or SharPoint site access is required for admins to manage membership. Membership assignment can also be automated with various tools like PowerShell or Power Automate.

Users can see only the sites they have access to, and will not suffer the bad user experience of clicking a library, only to get an error message for "You do not have access".