Studying different sports may seem like developing your mindset according to the op, but to me I prefer focusing on football sports because following up different sports makes me lose focus. Football is one of the best among all, very seamless, effortlessly, tiredless and interesting to predic and analise than any other sport. So studying others sport may develop mindset but in other hands make a person lose focused from my own perspective.
Football is also the most popular sport and many fans are attracted to football compared to other sports.
But some people also focus on other sports such as tennis, basketball, Baseball and American Football are popular in America.
For analysis and which one is suitable to study, depending on everyone's interests, if football is the most understood then it is the best choice.
Developing a betting mindset for all sports may be a little troublesome, but it's good for a broader knowledge of sports other than soccer.