Build a custom Combobox to show a Form in VB.NET, Windows Form project, via .NET CORE 6

I would like to create a custom Combobox control, so that it shows a Form. It should be generic enough to show any Form. It should work as a standalone Combobox, as well as in a Datagridview.

It should be built in VB.NET, using .NET Framework CORE 6, in a Windows Form project. The full details are in the attached ucRichDropDown.pdf document