I haven't tried this recently (so maybe it has improved), but I had a similar conversation with DxO. I wanted to use Iridient Developer/X-Transformer to convert the Fuji raw files to dng, and then process to completion in DxO. While DxO did recognize at least some dngs, it did not like the ones coming out of the Iridient workflow, I wrote them that they were missing a great opportunity to add Fuji shooters to their potential customer base by not recognizing the dngs from Iridient. They didn't need to deal with the X-Trans format, they just had to modify the list of acceptable dngs, I never heard any more from them.
DxO obviously has a small number of employees, but they are not at all open to suggestions, and not interested in expanding the list of potential customers. Not hard to understand why they are in financial difficulty.