Just a note:
These "other black belts" were likely karate black belts, not "sword" black belts. So as long as someone looked decent and could cut, they would be ok with these guys. especially if they were "mcdojo blackbelts".

I know a great many karate teachers who pick up a sword, stand in a karate stance and swing the sword like it's a baseball bat. And other karate teachers think they're great. Real "sword people" think they're idiots.

I don't think Dana Abbott is as bad as these guys. There is useful information on the videos and he has some skills.
BUT..
What you should do next is perhaps find a "real" Toyama Ryu school and perhaps watch a class or demo. I guarantee you it will look very similar. But there will be something in the technique and the power of the cutting that you may not visually identify, but you will just sit there and say WOW.

There is a certain amount of hype in the selling of all books and videos. So I don't really care so much about the Kyoshi title and other things on the cover. I wouldn't even tell someone that the videos are a waste of money.

For a beginner, they may very well get you through the first year of training if you don't have access to a higher level teacher (and providing you don't cut your fingers off).

But for someone able to train with not only a Toyama Ryu instructor (or any style if Toyama Ryu is not available) these are probably not even going to be good reference material.