partial match between two columns returns multiple values in one cell

I have a sheet for products that with clients (multi selection drop down) who bought that productThe same data validation list of clients is used to populate another sheet of contact email addresses for every client (one client can have multiple contact email addresses)

I would like to get all the contact email addresses of all clients in one cell per product

Been trying out with textjoin and multiple partial match formulas, but don't seem to get it to work. Any help would be more than welcome.