With the back of a wooden hammer handle, tap on all the tiles please. Listen carefully to the sounds and take notes please. You'll soon be able to tell the difference between properly adhered tile and those that are not. If you've got too many bad tile, it's a do-over.

Now it's time for the tear-it-all-out-without-testing crowd to chime in.

So that is black Schluter just floating below with no tile next to it?

Since he tiled beyond the rim of the tub, he should have done a tile "sliver" to fit between the Schluter and the tub.

This was in my previous house, so I don't have a good photo, but look on the lower right corner. See how the tile continues to the floor, in front of the tub? I used quarter round matching trim tile, but it would be the same with Schluter.

That is what you are missing ... assuming Joe's test results go well and you know they actually did proper waterproofing.

You might not have hired a qualified contractor. There are resources available for consumers on The National Tile Contractors Association website that might prove useful. As a 40+ year professional dedicated to the tile trade, we are always disappointed to see the experiences consumers have with unqualified labor. Hope this is helpful: https://www.tile-assn.com/page/trade-professionals-consumers .

How was the tub waterproofed?

It was wterproofed with kerdi membrane- i saw that done before the tile was installed and it was solid.