I don't know if more robust displays are available or not.
Had similar problems with my project...
Arduino plugged into 12V DC wall power pack; my project had sensors and a relay board.
24V AC door bell plugged into doorbell transformer controlled by relay board.
24V DC solenoids with a wall power pack controlled by relay board.
My project - the sensors "sense" and the program tells the doorbell to ring or solenoids to fire.
On my project, whenever the doorbell rang, it interfered with the sensors on the arduino; thus starting a vicious cycle.
Everything got a little wacky on the arduino: display, sensors, relays, etc.
Tried diodes - no help.
What worked for me was having everything on the same cord. I used a 24V AC transformer (used 24V AC for doorbell), converted 24V AC to DC with a bridge rectifier and some capacitors (used 24V DC for solenoids). Converted 24V DC to 12V DC with a voltage regulator and a capacitor (Used 12V DC for arduino). Everything on one cord. Feedback gone! Not sure you can do that with your project or if it would work for you.
There are web sites to design your own power supply that have different filters and features. I'm not able to tell you how to do that but I did see them in my web surfing.