I got the confirmation today from EKL: Blackridge is not AM5 compatible and there are no plans for an AM5 kit.
RIP i guess.
Maybe someone finds a solution (i will have a look on the coming Noctua AM5 kit).
Der8auer also seems to develop a shortened backplate for AM5 - in that case it might be...
Needed a model of the Alpenföhn Black Ridge for a project, wasn't able to find one. Tried to ask Alpenföhn but they weren't very cooperative, so I made this model from their photos and drawings. It's likely not 100.00% perfectly accurate, but I'm confident it's about +-~0.5mm in most places...