Is it legal to write software that conflicts with copyright only for personal use?

Question

Law in IT

If I want, for example , to make a program that parses a video from YouTube and plays this video without ads, without unnecessary jerking of JS in the browser and without using a bunch of other unnecessary services.
It is intuitively clear what kind of mass distribution they hit on the neck.
But if you use it only for yourself and law enforcement find out about it , then what are the consequences? (and yes, I know they are very unlikely to be able to figure it out, but still interesting)

Answer 1

You need to read the specific license agreement and Terms of Use.
Most often, it states that interference in logic is unacceptable. Well, in the same place you can read about the consequences of the violation ;-)