Handling site with multiple homepages/menus that share content

I’m wondering if anyone would be so kind as to recommend a way to approach this situation.

Building a site has 3 ‘sections’ (customer, vendor, advisor). Each section has its own home page and have different menus.
a number of pages are the same on all sites (‘about’, ‘privay policy’ and for instance and some others)
menu at very top of site links to the different homepages

Requirements:

• on shared pages, current section is in the url ‘website.com/vendors/about-us’
• do not want to have 3 versions of all pages. content should be maintained in one place.
• always display appropriate section highlighted on the site section menu
• breadcrumbs that include the name of the current home page as first link (using the wpml breadcrumbs right now)
• header logo links to the current section homepage
• all the periodic content (posts) are on all 3 areas of the site
• must remember when returning to the site which section user was last using and default to that homepage (cookie?)
• when visiting the root domain, it will forward you to a specific section.
• site is using WPML, Timber and advanced custom fields

I’m wondering if any plugins would help here, or figure out the best way to accomplish this reliably

I have mostly created a function to handle the 3 home pages, 3 different menus, basically using advanced custom fields to associate a menu with a homepage and checking parents of a page to see which ‘section’ we’re in.

But it gets complicated when dealing with pages that are in multiple sections. The main issue is reliably handling pages with the same content appearing in multiple places. I have looked at creating ‘clone’ pages that have a field to specify which other page they mimic. this isn’t ideal bc there’s a ton of wordpress pages.

Getting page parents based on where it sits in the nav menu instead of the wordpress page hierarchy would be great (just know that some pages aren’t in the menu (linked within content of the page in question), but we could add them and just not render them in the view)

Would wordpress multisite be the way to go here?