Multi tenancy ASP.NET core

I don't think you need to search for a library or a framework to build this out, you can do the implementation as follows,

• Create a table that reads as ProductPermissions
• Make an entry for recordid, groupid, roleid in this table
• After a user is assigned a group, the relevant tables should have the values like UserDetails, UserGroups, UserRoles etc
• When I want to see the list of products that are accessible to me, I make a request to the GetProducts API.
• The API gets my userid from the authentication process, roles and group ids
• Now, you have to join the products table and the ProductPermissions table with the keys and filter by the groupid that I have been assigned.
• The same logic applies for all the entity operations that I do, any action will be validated against the ProductPermissions table.

Note

In order to get a generic table than redundant ProductPermissions, you can have the table as EntityPermissions and then have the entityId (ex: Product, Category etc) as a column and that will be used a filter during joining so that you have a single table for all entities.