Get your water tested. That will tell you what’s in YOUR water - including the city treatment, city supply pipes, and even the pipes running into your home. Do your research based off the values you see in those results.

If you do thinks it’s worth getting a filter, install one in the kitchen. That’s where you get your drinking and cooking water from. Not much sense in buying a huge system to treat the water that goes into your shower or toilet or waters your garden.