I myself find most success to get hookups where I live, central Stockholm, both because of tourism and people from outside the inner city visiting to go on bars, etc over the night. To find someone with brains to actually get to know and maybe even date, not so much. But it's pretty hard to tell since I've ofc also used it the majority of the time here where I live. Your example with Morocco is indeed a bad spot, spots with a Muslim majority (swedistan jk) population will find bad success IMO, it's pretty much very taboo, relations and sex is a taboo subject overall, and traditional Muslim families would like to actually dictate who their spouse is meeting/marrying, hence the random pictures. They can even take the risk to get kicked out if they are seen on such work of the devil as Tinder or with an unknown guy.
I found a very good ratio in Mexico, they probably thought I was American lul. But Russia was very good as well, like insanely good.