Unreal Engine REF in for genlock

I've been going through the documentation for UE 5.1 and the Timecode and Genlock pages mention that only AJA Cards can use a reference signal as a source for Genlock instead of the video source, is there any way to get this working with Decklink 8K Pro Mini/8k Pro or is this a limitation of the hardware itself?When looking at the desktop video setup the REF input is locked to 50.

When using the Blackmagic video source I've noticed unreal genlocking to 50fps with an 50i source, compared to a bluefish source in the same engine at 25fps, genlocked to Ref.