This is simple test cube of 20mm dimensions with a 10mm hole. The Fusion 360 file is included as well.

I had a lot of trouble getting TPU to print and wanted to share how I did it. For adhesion issues on the MK3s I used blue tape on the PEI sheet per the recommendations on the Ninjatek site for Ninjaflex site - https://ninjatek.com/printing-guidelines/

I then loosened the bondtech screw till it didn't catch the nut and then screwed it in only a half turn or so as soon as it caught the nut, so it is basically as loose as possible. I read this was important to prevent the TPU from winding around the bond tech gears.

For the temp for this filament from the link above it says 225-235 so I wanted to make sure it melted because in previous runs it was too gummy so used 247 on the first layer and 240 on the rest in my config.

I changed all the speeds to the lowest recommended, such as 10mm for the first layer. There are a few other settings that I got from the config file here which I started with - https://forum.prusaprinters.org/forum/original-prusa-i3-mk3s-mk3-how-do-i-print-this-printing-help/please-help-with-tpu-settings/ and then changed the following:

retraction length = 2.5
lift z = 0
retraction speed = 75
deretraction seed 35
first layer temp = 247
other layer temp = 240

print setting speed (15: all perimeters, support material interface, 20: infiill, solid infill, support material, gap fill, 10: top solid infill, 100: travel, 10: first layer speed)

I included the .ini settings config file for the Prusaslicer for the MK3s and the generated gcode as well. Good luck!

Note pics are of a version I made before I had the hole centered properly which is fixed now.