Just to say it, TDS is not an indicator of water quality.

If I was doing something I would personally get something like a Filtrete or other good NSF certified water filter, and put it under kitchen sink for drinking water/food water only, and have it come out of a sink faucet and tap it to refrigerator and bypass the built in water filters.

This is what I put in my mom's house.

https://www.amazon.com/gp/product/B01L0ADH3K/ref=ox_sc_saved_title_2?smid=ATVPDKIKX0DER&th=1