My feeble searches for this have come up short. It seems possible, because of the existence of things like "DROK Buck-Boost Converter, 80W"
https://www.amazon.com/dp/B0BQBXMH67 for only $22. I have one of those, and it works satisfactorily for my needs. You can control both the voltage and the current-limit separately, using one digital control knob and some buttons. The adjustment response is slow: apparently they are driving the DC-DC block with a PID loop implemented in software that relies on the slow ADC (maybe 0.5 sec per update) that also drives the I and V display, so in response to a step change, you can observe the voltage and current bounce around for several seconds, before settling.
At any rate it's good enough for my project, and it is clearly using a MCU with strictly digital inputs; several switches and the push / turn rotary encoder control. I guess I could hack those, but I'm just wondering if anyone took the next step and offers a similar item with external serial port or USB port that accepts voltage and/or current setpoints. I understand "programmable power supply" is a standard item, but the models I know about are in a different price class, in exchange for better performance in ways I don't actually need. Given the existence proof of a $22 item, I was imagining a serial-control-capable version of the same thing might be only slightly more.