DPS5015(0-50V/0-15A) and DPS5020(0-50V/0-20A) are DIY modules available for ca 40.- USD. It exist several of these. Notice that input here is 60V DC, so you need a AC/DC converter in front of this.
I have looked at these for a while as I plan to build some Lab PSU’s. It is an interesting option. The USB/Bluetooth adapter with the software below is very interesting. The module uses a UART With Modbus RTU – the protocol doc is in Chinese, but I hope someone will translate this to English.
One can never have to many lab PSU’s ….