Hi folks. Good news.
RayCarrot made a modification of his Rayman Control Panel which allows modifying Rayman 2, 3, M, Arena to use high resolution textures in PC versions.
Easy and comfortable tool with texture browser, allowing also multiple edits.
viewtopic.php?p=1365628#p1365628
viewtopic.php?p=1365628#p1365628
Bad news -
Filenames won't match from this mod, though, so if no one will find better solution, all Dolphin texture names will have to be renamed to PC names manually.
And I afraid it will take ages if no one gets on a better idea. Maybe sorting all textures by size will help to match them? I don't know. I don't even think about some software recognizing duplicate images. It would be too great. Still, it could take ages as well if it won't have some auto renaming feature.
Another idea is to upscale existing PC textures by AI upscaler called ESRGAN using an e.g. Fatality algorithm like Granville did in Rayman 2, but it won't look as good as ICUP321 tex mod based on console official HD textures, but still, it will be noticeably better.
But, in case of using ICUP321 tex mod, I'd highly recommend using my upscaled version of these textures (not by ESRGAN, but Lanczos filter in XnView Classic, but they're sharper in FHD and greater resolutions):
https://yadi.sk/d/5EpdhiN2aY6NZQ For some reason, I've never even linked to this package anywhere before -.-
They're already in form of separate texture files instead of package for Dolphin, so they're easy to convert/edit/view.
On the other hand, for people using my Reshade mod for PC version, tex mod is not absolutely necessary since I've used there few good sharpening shaders, and these textures doesn't look bad in comparison to HD version counterparts:
viewtopic.php?t=28380
But for vanilla PC version, HD tex mod would be like a salvation. Even ESRGAN Fatality upscale with PC textures as a base would make a difference.