Well, Monaco's tricky, but, it's full downforce. Everyone knows how to set cars up for Monaco; it's a tight, narrow, bumpy tracky, that would especially reward somewhat softer cars.
Singapore's trickier. "Do I run full downforce? Sectors 1 & 2 are somewhat long straightaways. If I can't open DRS, I'm a sitting duck.

Some of the corners aren't that bumpy.

Maybe I should run a stiff setup. But, oh no! I should be able to attack the curbs, a bit, at Turn 5/6 and turn 10, and maybe turns 1/2/3.

How do I know I'm getting the setup right?

"
Monaco is bumpy, effectively, in every corner, and it's smaller, and tighter, and the fastest spot on the track is a turn, leading to a sharp chicane, iirc.
Singapore's like another Spa, in a way; you've got a few straights, and a few turns. Should you run full downforce?
Monaco's only a great race, because speaking French is so much fun, and, maybe because of the billions of dollars worth of yachts... and maybe the famous people... and the French riviera... The races themselves are usually, if I'm honest, a bit lacklustre, due to the impossibility of passing.