Your current setup is more than sufficient for showering, washing dishes, toilet flushing, even brushing teeth (though I would understand if your wife was doubtful on the last one).
Add an undercounter RO system, I've been using Amazon systems (
https://www.amazon.com/APEC-Water-Sy...00HRHHFPW?th=1). That will get you to essentially pure water for drinking.
The tradeoff for the cheap RO system is that its pump is powered by your water supply. That means you have about a 3:1 usage of water input to filtered output. The system uses the water pressure to drive the pump that forces water through the RO membrane, that "pump" water just goes down the drain. If you have concerns about your water availability (I don't think so), or your drainfield (maybe?) then that is something to consider. You can also redirect the pump drive water drain into a separate holding tank and use it for irrigation or other things.
The next step up would be a watermaker, like what you find on yachts and fishing boats. That will set you back about $3,500, and is probably overkill for what you need.