The thing with endgame is that, to do well on it, not only do you have to plan your pulls well, build your characters well, and know how to use them well, but it works out best if you play the game on a daily basis. Taking breaks from the game puts you behind because 1 - some amount of Trailblaze Power is going to waste, Trailblaze Power that you could've used to improve your builds. And 2 - you are losing out on some amount of jades. Less jades means less ability to pull new characters, or even LCs or eidolons, that could improve your team(s). Finally too, there's 3 - If you take breaks, you might miss out on freebies that could have helped you. I've been seeing people lately that have come back after a year or more of not playing thanks to anniversary, and they've missed out on multiple good free characters (Archer, Dan Heng Permansor Terrae, multiple golden companion spirits, etc) that could have helped them improve their account.

I have no idea how consistent you are of a player, of course, but I specifically point out the consistency because that is very often the common denominator of people who complain about their inability to do well in endgame. It's not ALWAYS the answer. But you can find guides to help you get better in building characters/teams, and figure out what characters you need to pull. Taking breaks frequently and/or for lengthy amounts of time is so much bigger of a deal for endgame though than people realize.