I have been using one of those for about a month, and I absolutely love it. I have multiple display profiles, all acting as triggers for custom functions when switched to, using the Stream Deck as the macro button to switch profiles is a bliss. It is a bit annoying that I have to come up with all these different keyboards shortcuts though.

It would be amazing to see a plugin so we can directly assign DF profiles and custom functions to it in the Stream Deck software.

I can not beg enough for this integration. I would use it without exaggeration 25x per day

If it's just for switching profiles, afaik you don't need to assign shortcuts.
You could just use the DisplayFusion Command Line Tool:
https://www.displayfusion.com/HelpGuide/DisplayFusionCommandLineTool/

e.g.:

I have done it since then. But I'd still like to see a plugin, as it's just more convenient to drag and drop functions onto keys.

+1 from me too, I would love a plugin and/or profile. Lots of abilities in DisplayFusion that I don't remember all the shortcuts for and being able to put them to an icon on my streamdecks would be awesome.