If you don't mind fiddling yourself to get something up and running I personally would go for something like a Meanwell RSP 24V or SPV 24V power supply.
For example I have a RSP-1000-24 unit in my drawer and when the problem with "it" came up in order to test if it was the HDPLEX 250 at fault or the DC adapter, I used the RSP-1000-24 to test the setup with 12V, 19V and 24V to see if that would cause the system to crash and it didn't.
Simply put the RSP and SPV series from Meanwell can be controlled by an analog 0V-5V signal, so you can go as simple as just a trimmer pot and measuring with a multimeter to get your desired voltage or go ham and automate it using something like and Arduino.
Something like the SPV-300 or the RSP-750-24 should cover most of your needs in terms of voltage and current I'd presume
SPV-300 could be had around $70 I think
RSP-750
Another option, that I had at my previous job, is a regular lab power supply.
I thought the one I used was relatively cheap but now I see it was €400
, makes sense I guess since it did 32V - 30A
Peaktech 1580
Here's a downgraded version at only €175 -_-
You can get
others that are much cheaper, but I can't vouch for the quality
I hope that can point you somewhat in a direction. If you have specific question about the meanwell solution feel free to ask.
With the lab power supply I can't offer much more insight.