People will get one for their whole house, which is great unless your home has leaded pipes…
It sounds like something people would think of, but they often don’t.
If your house has leaded pipes, you can get a small RO either by your sink, or before the hose that connects to your fridge is a better plan. It doesn’t have to be by your fridge, it can be where the hose meets pipe which is usually out of the way.
The real solution is replacing the piping, but that shits gets expensive.
A small RO to your fridge is doable even when renting, and if you get tests done and it’s high, some landlords would pay it just to show they’re not liable and did something to address the issue if it’s high.