Ultrasonic sensors are not showing proper value?
First, Check and verify that Trig and Echo pins are connected properly and jumper wires are not loose. Also, confirm the same pin in the programming as well.
If your Trig is connected on D1 and Echo on D2 then make sure that the programming block match with that.
Can we use a 5V ultrasonic sensor with Quarky?
Use the Ultrasonic sensor provided in the kit, additionally, if you want to try out the new sensors on your own you can surely do that.