Can I do my PPL on an Esta? (European National)

I'm planning on doing my PPL in the U.S. I'm mostly looking at smaller part 61 schools, and I was curious if anyone has any experience with doing a PPL under VWP, visitor (b) visa under Esta. The schools I'm in contact with have very little to no experience with international students, hence limited experience with M-1 and F-1 visas, so I wanted to check if this is possible.

I would probably be in the country for a maximum of 2 months, as I will be studying online ground school prior to leaving. This would obviously be less than the maximum duration of a visit of 90 days, but will it count as either business or tourism? There is a lot of mixed information about this online, so I hope someone is able to provide a more or less concrete answer to the issue.

Thanks a lot for reading!