intermediate openings

i think you will get the most returns from training simple tactics and basic checkmates at this point of your chess journey. also give yourself time to figure things out. play 10 minutes or longer. in order to be good at playing fast, you need to be good at playing slow first. you need to develop good habits and you need to think about these consciously before they become second nature to you later.

as for openings, i would propose keeping it simple. keep playing 1 e4 as white and 1 d4 d5 as black. play 1 e4 e5 as black too. but at any given turn, pay attention to whether you can win something or force a checkmate. if not, then only then do you proceed with developing your army.

your goals in the opening should also be simple enough to carry out.

develop the minor pieces, especially on the side you want to castle.

castle to get the king to safety.

move the queen to connect the rooks

prepare to gain space with your pawns or simply open files for your rooks.

all this should be done with the caveat "unless there is a tactic winning material or forcing checkmate. in this case the tactic overrides everything, because it allows you to win the game."

These opening courses are prepared for level 1500-2200 but you can check them out https://chessmood.com/courses all courses prepared by grandmasters