The default settings are definitely a large contributer there. Once you change a handful, it should be better. Worth mentioning though, there is still a noticable performance drop as the city gets larger, supposedly the biggest drop is early on ie 0 population to 2000 or so, from what I’ve heard.
CityPlannerPlays has a video up for what settings are important to play. Personally I will mention that in the “advanced” settings you can change the AA to “TAA” which should be better than the others, it’s just hidden in the normal menu. I imagine DigitalFoundry will have a in-depth performance/settings video up sometime soonish, but I have no idea for sure.
Edit: if I had working eyes, I would have seen that they put their own suggestions in the steam post as well. Either way, worth checking out CPP for addition info I guess.
Don’t forget the mods! They make a big difference IMO.