If you need a dual encoder for your panel, you can make it yourself using two cheap encoders and two gear wheels of the same size, as shown in the picture.Two tubes are used as the handles for the encoder, one sliding within the other.
The inner tube is solidly connected to the shaft of the 1st encoder, and the outer tube is connected with the gear, which transfers rotation to the 2nd encoder.
At least the first encoder can have a usable built-in push-button switch.
You can make Coaxial Dual Encoderl, using two cheap encoders ($0.3 each) with plastic shafts, as shown in the picture.
Drill the encoder shafts, take a metal rod, insert it in both encoders and fasten on one side.
For this construction these cheap encoders with plastic shafts can be perfectly used.
The diagram shows one cheap encoder with plastic shaft and second is the "mouse" encoder. As an option, a simple cheap button can be used as switch.
Budget - about $1 for two encoders and one button.