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

1. Wash the plate to help with adhesion
2. raise z offset just a tiny bit
3. if possible add a chamfer
4. if adhesion is still a issue add a brim