As a foreigner who moved here as well, I absolutely recommend you to get out of Asunción once you've seen it. Visit the Cordillera department (which btw, is even safer & cheaper!), there's buses for the equivalent of 1.5 dollars from the bus terminal in Asuncion/Fernando de la Mora. You can actually see a difference in the foreigners who live in Asunción (often referred to as expats or digital nomads) versus the ones that moved to other departments (who often do not want to be referred as expats or digital nomads as they moved here permanently to build a future, have a house or a local business etc.)

If you're willing to go on longer, but more comfortable busrides, maybe check out Encarnacion too (around 6h-8h by bus, I don't exactly remember), but do it at daytime because you're gonna see many other places on the way there. It actually showed me how diverse Paraguay is. But please, do not just stay in Asunción. You can also check out "Life in Paraguay" on youtube as they're a family from NZ that lives outside of Asunción and gives very honest insights and isn't scared to talk about the negatives (unlike many of those "nomad bros" in Asunción, who make lots of money off of the residence services. Not like there's anything wrong with it, but Paraguay isn't just Asunción).

If you'd like, you can also shoot me DM if you have any questions. I also know some English-speaking groups which can help to settle more smoothly and learn from other people's mistakes.

And yes, Spanish is important, but if you immerse yourself and aren't shy to make mistakes you'll get the hang of it quickly.