A possible workaround would be to use the Adobe DNG Converter which is free and allegedly supports the Mini 4 Pro. Point it at a folder of Mini 4 DNG files and it will convert them to another DNG which I am hoping will have a colour profile which affinity understands.
I used it on my Mini 2 files and the result was the same in Photoshop and Affinity Photo 2. The Mini 2 is supported by Affinity Photo so that may not prove anything.