To get some insight into the IDT science for cr2, you can read the pdf from doi (use the download button on the page):
https://doi.org/10.2352/ISSN.2470-1173. ... .MOBMU-138They are comparing several non-propriotary RAW converters. It's for the EOS 5D mkIII. From my experience, the results are similar with the 7D and the 5DmkII. Resolve is actually a little closer to the correct values than Photoshop. Affinity gets the closest. But the Resolve IDT is acceptable. Things might be different for other cameras.
If you have shot a color chart and use it to balance out the offsets from the IDTs the result should be very close to the actual image. This is at least the case for me with the cameras mentioned above.
If your images look extremely wonky as you describe it, something is set wrong. But unless you use Canon's DPP for conversion, the image will never be perfect. DPP unfortunately limits you to photographic color spaces.