Yes, Affinity should be able to handle this you are right. Makes it pretty much useless for multipass rendering.
But on the other hand I wish there was a way to just save out non linear PSD files as for me at least linear files are problematic, like there is a colour shift if you finish all your editing and save out an sRGB Jpeg which can be frustrating. I find it safer to just do everything in sRGB so there are no surprises.
I already save out of PV as the corona options are very limited - something I really wish could be fixed. You only have massive EXR files or compressed 8 bit file options. a 16 bit PSD or Tiff would be really helpful. The problem is that the PV saves out linear files, so I was wondering if there was anything Corona could do to stop the linear pipeline as it gets sent to the PV for saving. I think this is only a problem with multipass files but I could be wrong.
"or using the "Save" option in render settings and selecting a color profile there."
This could be interesting - I cant find this, which render setting are you referring to? Thanks