My guess would be that the RO filter is dumping a bunch. They seem to use 4 gallons for every 1 gallon of filtered water [1]. I personally do't like RO water, it tastes off to me and I appreciate having a. little fluoride in my water to fight off tooth decay.

[1]https://americanhomewater.com/the-truth-about-reverse-osmosi...

I lived overseas for a bit somewhere where you have to have an RO filter to drink from the tap. Nearly every filter on the market has mineral restoration packs which I think help with that bland water RO taste. One of the servicemen who changed our filters once warned us that the calcium in our purifier was so low that our bones would lose calcium. While I don’t know if I believe it, it was interesting to learn that minerals in drinking water can benefit health

I kind of miss making coffee with water out of that purifier though, it tasted noticeably better

Like I said, my main concern would be the fluoride. I actually really like the water here in NYC tastes great and seems good for baking, brewing beer, and coffee. Though I've never tried RO coffee.