@hebigt , So let me just expose my understanding to your post. With that coming new board Duet3 read the encoder pulses ( hence, know the absolute position )

in theory, you could continue with your current servo drive, send the encoder signals to the duet closed-loop board, and send the step/direction signals to the drive

Still, even if the Duet3 will send Pulse/Direction signal to my motor driver, I cannot do anything with that signal because my motor driver only accept an analog 0-5V signal for controlling the motor speed.
I think I would be better of to just change my motor controller against one that utilize Step/Direction and connect the angular encoder on that new driver. This way the Duet3 would only wait for Ready state to continue the program.
Am I getting this correctly ?

I have this machine equipped with an analog motor and driver with an angular encoder. The motor driver will accept an analog signal from 0 to 5Vdc for speed control. Another input is DIR (direction, 0 or 5V ). The encoder pulses 2000 counts per revolution. The encoder is not connected to the driver, rather, it is connected to the local SBC that do the positioning computation. I want to get rid of that broken SBC to replace it with a Duet 3 board. Further utilization of my machine would then become available through Gcode.

Is the Duet 3/RepRapFirmware capable of implementing the control of my Servo motor arrangement ? Is the Duet 3 board capable of reading the angular encoder pulses ?