You can watch the Bahrain–Curaçao match here if interested.
Watched first 8 mins. Curacao actually hit the post at 4.30mins approx in.
0-0 until HT & 1-0 until 84 mins. So final 4-0 scoreline likely misleading.
Bit like AWs, Curacao have some guys at a high level, and then some down in 3rd-4th tier/U21 football. Some at even lower levels than the AWs.
So if Kluivert made a heap of subs as per normal in a friendly, their team that finished the game may have been a big drop in quality from the starters. He's likely experimenting too, as a fairly new coach (replaced Guus Hiddink this year), with no major CONCACAF comps again until 2023??
Bahrain on the other hand have the Arab Cup, coming up in December. So perhaps a bit more in serious mode currently, with less dabbling.
Edit - see Curacao started their big guns Bacuna bros & Anita. Roly didn't start.
https://www.sofascore.com/team/football/curacao/55827