These difficulties are well known. I want to tell at this point something out of my practice.
When I first started more than 5 years with the chess game, I was very ambitious. At that time I was 14 I bought a book by Rolf Schwarz Opening "French" and tried to memorize variant of variant. This is difficult, because even after a few puffs gives rise to many branches that one can no longer remember all of them.
Then came the first few games. My opponent took 1st e4 and I answered with 1 .. e6. After a few more trains pulled my opposite a train, I knew from the books any more.
Then came my big moment! I thought, "This train has to be wrong" and then tried to refute this train. With little success. Most of the games were lost. Why?
Because I had from the very meaning of the opening no idea. The stubborn memorizing opening moves will take you further. It prevents a targeted chess training and wasted much time.
More importantly, it is familiar with the plans to put behind the openings. Then the transition between the opening and middle game is easier.
If you have gaps in the middle game and endgame, then there is no point in focusing on the opening. You should first turn off your flaws in these areas! Then you also find it easier to learn new openings.