Starting from the beginning, I should mention one important point;
if you intend to learn martial arts, you have to take classes from a teacher and you have to practice sparring with other students. There is no getting around this.
A lot of people seem to think that they can just read something, watch something, then practice on their own.
This will not work, you will make beginner mistakes, learn the wrong stances, not get basic movements right etc, and no one will correct you. If you practice sparring with a friend who also learned this way, you may seem to do well, but you're both amateurs and you will cover up for each other's mistakes.
When you train at a dojo or other public facility, you will meet people who are not your friends. They will not go easy on you, and you will see at once if what you learned worked or not. The teacher will correct your flaws at once, and you can learn it right from the start. If you learn it wrongly, changing a movement routine later is very difficult.
With that said, once you have these basics down, you can practice on your own, because you have a mental framework to place these methods in. At this point it's easier to watch a video and correctly understand what is being shown.
When it comes to the self defence methods in the OP, those can be learned as they are, but having martial arts experience helps. If you only want to do it to expand your perspective somewhat, then those are fine.
These are my views on this.
I've seen a lot of imageboard posters talk about martial arts and how to learn it, and unfortunately most think they can just punch a bag after weightlifting with no introductory instruction and then they know how to fight. Do that and you end up like that guy on the "martial arts journey" youtube channel. He learned aikido to master level and started his own dojo, but never sparred. Then he was assaulted in the street and couldn't defend himself. He decided to test his skill vs an MMA professional and couldn't get a single technique in. Don't be that guy.