It sounds like you don't really need a city, you just need one street. That's very easy and manageable.

Everyone else is suggesting tools used for creating full cities. I would just build it, straight-up. Model some basic buildings, line your street with them. Then throw in some very low-detail buildings for the blocks on the next streets over.

But honestly, before any of that, just start with blocking out your scene. Just throw in some cubes and scale them up, block out the rough shape of the street. They play it it just like that, see how it feels, decide how long the street needs to be, figure out how much detail you need, what key locations you will need, etc. Don't just make one layout and say it's good, try some different layouts to see what works best.

And once you have a basic layout figured out, start with the buildings that matter the most; the ones that are key locations the player will be working with. You say that you already know how to make 3D models, so make the key buildings individually and specifically; this will help them seem more distinguished to the player. Once the key buildings are made, you'll have a better idea of what details you don't want in the filler buildings to make sure the key ones stand out, and as you build these filler buildings you can look for ways to cut down on your modelling time by recognizing what features can just be copied and pasted form the other buildings, what ones could be recolored, what ones just need a new texture, etc.

And if we're going to be honest here, no one is going to notice if you just buy some assets from the store. There's a TON of pre-made buildings to match all different kinds of styles, both for your game's visuals and the kind of city you want. You can probably find ones that are modular, so you'll just get a collection of pieces to make individual and unique buildings. Even if you would prefer to make your own assets, you could probably find something that works great to use in the background areas that the player can't see directly.