metichemsi I wasn't aware they were filming in 30FPS though SLR does interpolate to 60 FPS so that may have been part of the issue but KinkygirlsBerlin filmed in 8K 30fps because they used the R5 and they didn't have big issues(though not ideal to interpolate)
The biggest SLR Original R5C issues early on were the fisheye like you said and #1 was the scenes appeared out of focus which I don't know if it was from user error or lens issue. This was their first R5C scene https://www.sexlikereal.com/scenes/big-tits-at-the-glory-hole-26692?tab=downloads
Apparently, they have remastered this which I haven't viewed yet but from 11 months ago they commented " SLR Originals - Evan, Head of Post-production 11 months ago
yes, I agreed, this scene is slightly out of focus, we need some time to handle this new camera. "
But yes equirectangular conversions is such an important thing along with the age old challenge of placing the camera and model just the right distance which is something that has been always a challenge for all studios(though some are more consistent that others). R5C is probably more critical to get all of these things aligned precisely. Other challenged I have seen with the R5C is that Canon Raw Light can be extremely noisy if not used with certain settings. It's a known issue and some theorized that Netflix rejected the R5C from their Netflix certification because of the RAW. NaughtyAmerica is using the R5C and their early releases with it were completely unwatchable because the entire thing was noise(they corrected much of that since)
Definitely a challenging camera from what we've seen. WankzVR and StripZVR commented they wouldn't use this camera because of the IPD but there seems to be ways of making it work.