Fair use isn't that simple. It's possible in some circumstances to change very little and still be able to win a fair use defense, and in other circumstances to change a lot and still be found to have infringed the copyright. I encourage you to study how it actually works, and maybe ask a copyright attorney. In fact, I happen to know of Leonard French, an attorney who talks a lot about copyright (including fair use) and other topics, as well as various cases in the news, on his YouTube channel.
That said, the DMCA is being abused a lot. Something needs to be done to stop that abuse. Lenz v Universal was a step in the right direction, but I don't think it actually did as much as it could have. It's even worse when people make DMCA claims that are completely invalid, as e.g. someone did sometime back to Imagos Softworks and quite a number of their fans. At least they got a positive resolution, but a lot of damage was already done.
I am against too much federal, corporate, technological, religious, political, cultural, centralized, financial, tyranny, control, suppression, and YouTube removed thousands of my home videos I made on my OJAWALL Chanel, videos I made when I was ten years old with family and friends with no background music. Just little kids running around having fun. Gone.