Has anyone else had problems with an update for pacman on these? Or is it just me?
It seems that the update to pacman 5.2.0-2 causes a compatibility problem with yay (and kalu on EndeavourOS) as they require a version <5.2.
It’s easy enough to just NOT update the pacman (via pamac - these names, really?). I assume yay (and kalu) will eventually get updated to work with the latest pacman again.
I probably don’t need yay on ArcoLinux but it’s there now.
Uninstall yay, update pamac/pacman, then reinstall yay.
Worked for me on both Endeavour and Salient 
Thanks, I must have missed that combination - I did have to remove kalu (it still objected to pacman 5.2) which is probably no great loss but it was/is part of the original. I’ll keep checking to see if they update at some point. I may not use it, but it’s like those links you take out of a watch bracelet, you don’t use 'em but you don’t want to lose 'em either.
When I was trying Endeavour a few days ago I removed kalu as well, and installed Pamac, which is a far better app IMO
I put pamac on straight away, it’s better for searching for packages - kalu is too complex for my aging brain
Using the command
upall
in the terminal fixed all my ArcoLinux updates/add/remove woes.