That's right, when you want to understand many things about a sport like football, then at least you have to watch a lot of matches and find your favorite team. The more involved you are in it, the easier it is for you to analyze the game and I never thought it was difficult. Even 15 year old children can analyze a match when they really like the game and their team.
It is not recommended to gamble randomly when you don't understand the game, it is the same as gambling in the hope that you will get lucky. In sports betting, analysis is important and usually gamblers can increase their chances of winning when they understand the correct way to analyze.
Seeing your words about the favorite team selection, another thing that came to my mind is to watch the games and select your favorite sport.
Although you don't have to select it, it happens automatically due to human nature, but if someone wants to know about that sport by identifying it, I think they will be able to learn about their favorite sport in a much shorter time than it would take to learn about other sports in depth.
And at the same time, I will agree with you here that we should only bet on sports that we have a good idea about, although many will say that everything in gambling depends on luck, the results of sports betting also depend on some analysis, although in the end it all depends on luck.