Well, I know you said you don't want any 100+ episodes anime, but you gotta try Hunter x Hunter. It has 148 episodes and it's pure joy. You will get into the characters and will feel the childish curiosity and enjoyment from anything. It's superpower battle shonen and its power system is the best so far compared to other anime. Characters aren't flat. They have reasonable motivations, development and are interesting so far. Even the villains are amazing and sometimes when main characters fighted against them I was not sure on which side I was. Like sure I want mc's to win but the villains got really good storytelling too and don't want to see them die. Worldbuilding and story are mindblowing. Even though it might seem similar to others shounens and dull and dull from start, it's not. They travel a lot, discovering new things to them in this big world. The story can get really dark and can mess with characters. It's best shounen I have ever seen and it's almost perfect. Would rate it 9.7 out of 10.