New to Sharepoint and Teams_Client folder structure?

We are a small landscape design/build company moving from Microsoft 365 Family to Microsoft 365 Business Standard.

Currently, we use a traditional folder system:

Clients > Client Name > project files

Each client folder contains estimates, proposals, Vectorworks CAD drawings, site data, photos, PDFs, spreadsheets, and other project documents.

We also have other company folders for employees, equipment, systems, vendors, templates, and SOPs.

We have four office users who need to access and collaborate on these files through SharePoint/Teams.

What is the best practice for setting this up?

Should we use one SharePoint site with document libraries, separate SharePoint sites by department/category, or organize everything through Teams channels?

I’d like to understand the best way to use SharePoint and Teams without simply recreating an old folder system incorrectly.