Improve ride quality? Change rims?

Check the COLD tire pressure. Alot of Prius owners run high pressures.
36psi for the front, 32 for the read. Check the sticker on the door frame.

How many miles on the car? The strucks and shocks could be worn out.

 

You need tires with taller sidewalls. You did not list your model or existing tire size but most 2010 models had P195/65R15 tires which have a better ride than the 17" tires.

So the next step is to inflate to the door sticker. Do not over inflate.

Then consider better quality, better riding tires with lower road noise. Michelin is my choice for those goals plus you get 80,000 or more miles from them.

Finally, the car has almost no sound proofing. You could add some under the carpets and in the doors. Possibly under the hood.

Bottom line, Prius is made for mpg and low weight. So they came with hard riding low rolling resistance tires and no sound proofing. Some guys jack up the air pressure to squeeze more mpg at the expense of the ride and noise. Your choice.

By the way, the Prius v wagon rides better in part because of a special pitch and bounce control.

 

New KYB Excel g shocks

 

Second this. A lot of people here run their tires with max-pressure. I don’t know how they do it but they must live in areas with nice roads. I live up-north which is pot-hole infested and its impossible to run my tires with high PSI for fuel efficiency without affecting comfort significantly. Even at 35 psi my prius was unbearable and irritating with all the bumps in the road. I found 33 psi to be the max I could go.

 

@newguywithpups , as @rjparker mentioned, your model is described as “N/A” in your avatar, which leaves responders guessing regarding your rim size, 15” or 17”. The latter ride harsher for sure. Please clarify.

Also, what pressures are you running?

 

I was thinking air suspension so you can maanually adjust ride height.

 

Tire pressure is kind of a personal preference thing. 28 PSI to 38 PSI relatively speaking you're within range. Every single setting for beaches can be debated but Choose what you like. Each has its own benefit and it's own drawback.

Princeton some New York City with one of my cars right now. 15 inch rims with a high sidewalk. I'm at 32 psi. Pressure is never going to affect my fuel economy. This is all stop and go. I want to absorb the bumps and I don't think I'm going to ding the rim.

In Florida I have a Prius I use as a daily driver of the pressure set to 36. The sidewall and those tires is a 60.

 

Stick with the stock size. They are already as close to pillows as you can get. The air in the tire is a spring, and the sidewall height is the spring travel. So basically low pressure and tall sidewalls will give the best ride. I agree michelin touring tires are as good as it gets on noise and softness. You can glue in foam pads to the inside of the tires to make them slightly quieter, and add insulation to the car every where to go quieter.
I have never had good luck with KYB though. I would go OEM as say if kyb makes the oem shocks and struts for Toyota they have to build them to Toyotas quality standards or Toyota will **** them and send the whole order back and tell them to do better. lol
I typically just use Bilstein for shock replacements. They are great! Toyota uses them too sometimes so i wonder how they have changed them for their use case...
My ls400 has 225/60/16 tires stock. I could close my eyes and try to guess if i hit a dog, a kid, a pot hole, a curb. I honestly wouldn't be able to tell you. 225/60 is very similar in sidewall height.
I put 255/40/19s on now though and it rides like a normal car now though. lol

 

Since it that's old, it may be smart to get a trustworthy mechanic to lift it up and give all the suspension a good inspection. (Say that three times fast!)
There's quite a few rubber parts that do wear out over time and can cause horrible noise...even motor mounts can make a racket!