Search from Home Site and Global Navigation

Hi everyone,

We are currently in the process of creating an Intranet for our organization. Our landing page, called HomeHub, serves as the main entry point to our intranet and is registered as our Home Site in SharePoint Admin Centre and enables Global Navigation. It is also registered as a Hub Site, with 22 Department sites (11 Communication Sites and 11 Team Sites, one for each department) associated with it as their Parent hub.

Additionally, we already have 830 sites (a mix of communication and team sites) that were created before the Intranet was established. We will need to clean up these sites throughout the year.

I have two issues that I need advice on:

1. Search: Currently, the search functionality is working well because I registered the landing page of our intranet (HomeHub) as my Home Site. However, it is searching within all 830 sites. I want to restrict the search to only include the Home Site (HomeHub) and the 22 associated sites. How can I achieve this?

2. Global Navigation: I would like the Global Navigation to appear at the top of each site, including HomeHub and all associated sites, rather than just in the app menu. How can I accomplish this?

I appreciate any guidance or suggestions you can provide.

Thank you.