Advice about structuring a Sharepoint library / site please and saving as a template

[SarahTurner]

Hi, I want to create a Team site which relates to a single 'project' with a large amount of shared documents which will cover a wide range of departments who all contribute to the project.  

Each department wants everyone else to view their docs but not edit or delete them.  Some departments will share their docs with external parties such as contractors.

Can anyone comment on whether it is better to apply permissions at folder level within a single doc library OR have multiple libraries within the site and apply permissions at library level?  What are the advantages / disadvantages?

Secondly, if we apply permissions throughout the site, is there anyway of saving the site as a template (including permissions) to create a new team site for another project and it retain all the settings?

[#2]

@SarahTurner 

Personally, I would create a single Communication Site (as I have found this to be the best of the new modern site experiences), and then create document libraries for each individual department, as each department has their own permissions and sharing needs.  You can then apply permissions at the library level.  I think this will work better for you.

For how to save modern team sites as a template, take a look at this previous thread.  

https://techcommunity.microsoft.com/t5/sharepoint/save-modern-team-site-as-a-template-amp-provision-...

Hope this helps.

[#3]

@PeterRising thanks for your response - out of interest, what do you prefer about the communication site versus Team site?

[#4]

@SarahTurner 

Nothing major, just little things really.  For example, (and this may be me doing something wrong admittedly) I found that I could not centre a single column web part on a team site, whilst I could in a Communication Site.  I also found that on a Team Site, I couldn't get the top links bar working as well as in a Communication Site.  What I tend to do, is create a new Communication Site, then strip everything out.  I'll add a hero web part in a single column at the top, then under that I'll have the news feed and Quick links in a Single column with sidebar layout.  I think this looks really nice.  Links to dept doc libraries can be tiled below this, and then I'll add things like a Twitter feed or a contacts list and a few other things to pad out the landing page.