Show content based on user permission (group)

Oskar Kuus  , If this answer below was what you were looking for, could you please mark as best answer? 

The new modern sites consist of Communication sites, Team sites and ultimately Hub sites.

Communication Site, 
The communication site is way better when it comes to design, you have the possibility to use full-width web parts and the default templates that exists are perfect examples for why communication sites are meant to be landing pages. Communication sites alone are not so useful, they have no connection to Microsoft 365 groups and can not be connected to MS Teams. However, using a communication site as a landing page, it can be upgraded to a Hub site. To update the communication site into a Hub site, please visit the SharePoint Admin center and you will find the configuration button in the menu. I will explain more about Hub sites later.

Team site
The name really says it all. The site is created with a purpose to help a team work together. Microsoft 365 group is created and with these groups, you can add people that should have access to specific content. The Team site can be connected to MS Teams and that gives you the possibility to allow your users to communicate and work with files both in SharePoint and Teams. The strength of Team site connected to MS Teams is the flexibility to work everywhere. Co-authoring, chatting inside of documents and all secured while the conversations are saved in MS Teams. Team sites are powerful to handle teams and their content in a secure way. However, this does not solve your issue because you need one site that all users access, and see their own content, in a secure way. This will be solved by using a Hub site.

Hub site

The Hub site is created by activating the Hub site feature on a communication site through the SharePoint admin center. The Hub site by itself is not really anything special. However, in the SharePoint admin center, select your team sites and connect them to your new Hub site. By connecting sites to the Hub, you allow the sites to communicate with each other (something truly underestimated, hats of to the developers!). Connecting sites together, allows you to fetch data from any of the connected sources, simply by selecting the site while editing a web part. By default the SharePoint Search bar will be searching through your entire hub. The content shown and searchable is always content that you have access to. So when the access is handled by Microsoft 365 groups, you do not need to be worry about anything (as long as you do not have shadow admins).

Highlighted content web part

This is one of my favorite out-of-the-box web parts. It is included in SharePoint Online and you simply need to add it in your communication site while editing the page. When the web part is on place, you will most likely see content immediately. Click on the pen to the left of the web part (edit-icon), and there you will have the possibility to add or remove sites that should show data. Everything connected through the Hub site configuration that you made before. 

I hope this gave you some inspiration and idea on how to solve your challenge. For further assistance, please contact me and we will see what we can do. 🙂