Every single boss in Uldir has adds in one form or another, so none of them are strictly single target fights. But most of the fights have very few adds - often one at a time - so it makes sense to use the single target gearing strategy. The clear exception is Zul, which is a massive add fest. I’m curious if people use the multi-target strategy for any other bosses. Zek’voz is a good candidate, with the packs of silithid warriors in phase one.
If memory serves, back in Legion, the drop down box for single vs. multi-target strategy suggested which bosses went with each gearing strategy. I’d love to see that again, to get an idea of what you guys think.