… surprisingly don't mix all that well (yet?). 😆
Krita doesn't support .dds formats, but supposedly has a plugin for that, which doesn't seem to work atm.
Affinity (which I'm running through a Wine prefix) doesn't support the format either, but is supposed to be able to accept Photoshop plugins. Sadly, neither NVIDIA's nor Intel's respective plugins for Photoshop have worked during my attempts.
And then, there's GIMP. Ah, GIMP! I wish I had nice things to say, but sadly I don't 🙃 HOWEVER, it supports .dds out of the box, which is good! But the DDS exporter is… well, it def. c̸̦̑o̸̭͐m̵̟̈́p̴̗͌r̸̭̽e̶͖̎s̵͓͛s̷̭͌e̶͓̔ṩ̶ the texture alright, a bit too much for my liking.
(I should also mention Photopea, which also has support out of the box, but automatically applies the Alpha layer at import, so it's like working with a PNG… 😮💨 We can't have that!)
In any case, if someone else is wondering how to do it in a non-destructive way on Linux, here's my method for now:
Install the NVIDIA Texture Tools (NVTT) standalone utility (not the Photoshop plugin, they do the same thing however) through Wine ;
Import .dds image into GIMP ;
Do "File > Export as…" and select a common lossless format (e.g. TIF with the compression turned off) ;
Select BC3/DXT5 as the output ;
Choose the "Highest" compression effort (better quality, smaller file sizes, ""longer"" export time) ;
A convoluted process I know, but I haven't found a better way to go from DDS to DDS another way. Feel free to suggest your method though, I'd be happy to know 😁