Expanding on David's post, keep in mind that 4K discs are not region coded. So a cheap region-free BR player and a separate 4K player makes a lot of sense.
Presumably your existing players and TV support control by HDMI-CEC? Have you tried programming a universal remote to emulate your TV remote and then control your existing UHD and region 2 players over the HDMI cables rather than infrared control?The only problem I have with this set-up is that both players respond to the same remote, so when I use one of the players, I have to put something in front of the other to block the sensor.