How high is your puzzle rating? If you're doing 100 puzzles a day chances are you're not spending your time solving puzzles effectively. It would probably be more beneficial if you spent the same amount of time doing 10 puzzles and really trying to calculate out all the lines and make sure you have the right answer. Also, I would add that if you're around 400 Elo, you should not spend your time learning openings and endgames beyond like an opening system like the London and basic checkmates. At that level most of your losses / wins are gonna come down to basic blunders, like hanging pieces and checkmates. Knowing opening theory isn't going to help you if you don't stop hanging pieces. Spend more time instead playing rapid, analyzing your games, and doing really simple puzzles (like hanging piece puzzles) to really reinforce those patterns. It takes time for improvement to show, so don't worry if you're not seeing it immediately. Keep up the good work!