In my experience it was mandatory (for living fully integrated / working)
Supposedly Dutch people are all great at english but that wasnt the case at all in my experience
If you go to shops or restaurants they will speak English, but if you want to work anything other than unskilled labor you will need to learn Dutch. Even as a dishwasher they told me i should learn Dutch asap. If you wanna make friends and connections and stuff you should learn Dutch too (not because they would discriminate against you, but they just arent very fluent and they speak dutch between themselves)
Granted, i was in a small city, relatively speaking. Like, still an area city, but on the smaller scale. I dont know hows it like in the biggest cities
When i was looking for a place to rent, a lot of places reject you for not being Dutch. I found a place rented by another immigrant. Immigrant landlords tend to accept immigrants when renting, Dutch landlords tend to not. You might have a better chance being american than me being bulgarian though, i dunno
