You really don’t “need” to login twice a day. A single extra domain/boss drop isn’t going to completely make or break any content in the game. Even spiral abyss is only 2ish extra gacha pulls if you are really pushing it. Which again, won’t make or break any content in the game.
A huge amount of the event stuff is totally skippable, some minor lore here and there can be watched on YouTube, there are sometimes event weapons, but the majority of those aren’t even that much better than other permanently avaible ones, and certainly not over weapon banners.
I’ve been playing GI for almost a year, and it has been an absolute blast. I do the content I care about, skip stuff I dont. Its a fantastically fun game, that I can pop in go hunting for chests for an hour or two, maybe do some event minigames for pulls. If you have low self control and cannot bare to be 5% less effective in combat where you one shot everything with a single burst then it might not be a game you want to play, but for casual playing around and exploring the world fighting random monsters for happy treasure chest sounds, it has been an absolute delight.