Hey OP, just so you do not waste time. I mis-spoke and told you the opposite of what you should do in the program. No bevel, I meant chamfer!
I know it doesn’t make a lot of sense to make the surface area touching the build plate smaller but it is worth it since it provides relief from the layers above pulling when it is shrinking.










Not trying to be combative here but the tests you linked further support what I was saying. A small chamfer and I really mean small will have a similar effect once rendered in gcode to a fillet. If you have access to software to generate a fillet easily that is good too. That being said I would only do it for the outer rim.
Either way the print looks like it is warping on the lowest layers and has elephants foot which is what I suspect is the biggest issue here.
The steps I proposed are