Ok, I managed to solve this by issuing a rebuild on the arbtt AUR package.
So it seems the accepted status quo in the community is that each user needs to rebuild their own AUR packages every time something they depend on has changed. All fine and reasonable except that paru does not find the need to update any package when asked.
The thing that was fooling me was that no matter how many times I removed and reinstalled the package it would use cached data by paru so it was effectively checking deps but not doing the actual build.
I had to manually remove ~/.cache/paru/clone/arbtt
After that, paru -Suy arbtt trigger a proper build.
I'll try to find a section of the forum related to AUR and if this is not detailed there, post it with a more meaningful name as a solution for other users in a similar situation
I sill have the problem that cabal is using the wrong compiled libs to try to rebuild, so that is another story altogether.