Reminds me of the ones behind the anodize line at a former employer. The process for changing the resin in those is a bit trickier than unscrewing the bottom, but at least doing so is extremely infrequent.
Instead of RO they just ran 400 TDS tap straight into DI resin. I forget the flow rate, but it was on the order of hundreds of gallons per hour. The resin was of course recharged in place, but you don’t really want to deal with the chemicals that they used to do that.
At some point I remember the EHS guy explaining that the only reason it was so easy for us to dispose of acids was that we also needed to dispose of a lot of caustics. Drain them all into a 10k gallon holding tank, let the acids and bases mix to become salt water, adjust the ratio until the pH is near neutral, make sure there isn’t anything with additional disposal regulations mixed in, and it’s like flushing your water change down the drain.