Yeah, unfortunately the PCIE slot for this motherboard maxes out at 25W as well. And HP
really means that 25W limit; lots of people have tried to get a GT 1030 working on these HP SFFs without 75W PCIE slots and mostly run into failure even there.
There's a reason that PC came with a 19W GPU.
The sad truth is that old, small form-factor pre-builts meant for light productivity are really terrible candidates to try to turn into even an entry-level gaming rig. If you want to turn an old pre-built into an entry-level gaming rig, you'll have to start with a $100-$125 refurbished mini-tower with an i5 2400 or something, then replace the PSU and add a GPU.