Their pronunciation is impressive. It’s not perfect, but they’ve clearly put a lot of effort into it.
خ /x/ is really good.
ع /ʕ/ is pretty good. Slightly off, but it’s passable.
ح/ħ/ is okay for some of the singers, but they’re not hitting it properly. They’re realizing it as /h/ most of the time.
ل /l/ in Arabic is often light but they’re constantly realizing it as a dark /l/.
I’m impressed by how well they’re pronouncing the /x/ and /ʕ/ sounds, because they’re quite difficult for non-native speakers to pronounce.