David, thanks for your exhaustive reply. After I wrote my post yesterday I looked it little bit further into the structure of the .xml file you sent me and decided to create a new .xml for all three lenses using the RF16 2.8 data in the Lensfun file: mil-Canon.xml. The resulting file is attached below and it works like a charm! Maybe other Canon users can use that file also. Oddly enough the metadata of my RF35-F1.8 is recognized properly by Affinity so not all Canon RF lenses are a problem for Affinity.
I just deleted the Adobe DNG converter from my PC since it did not work properly but I will try your tip for the 70-300 mm lens also.
Hopefully all this will help to get some more bugs in the Affinity photo program corrected by the makers.
CanonR7-280-286-288.xml
FredD7 got a reaction from David in Яuislip in Canon R7 Metadata for lens type is incorrect in Affinity photo 2