TPU will be nearly impossible for your kiddo to destroy. ASA/ABS are rugged, but if your print has thin surfaces it’s less strong in my experience than PETG.

I didn’t find TPU hard to print personally, just go slow and turn retraction way down or completely off. It will string pretty good, but most slicers have a setting to avoid crossing perimeters that will keep it in check. The only thing I would be wary of is ending up with a floppy print, so make sure the part has some structure.