I should also say I have made edge connectors for soldering small boards to each other at 90 degrees and for my part I had to make an SMD part and then use it on both sides because THT parts all get holes in them. I did then place vias on every single finger to ensure both sides were connected.
I am attaching my edge connector part in case anyone wants to use it as a start for these connectors. I repeat, this one will not work for what you want but may speed up development. 20 Pad Edge Connector.fzpz (7.2 KB)