That's because they either properly prepared everything they needed before writing, they aren't putting too much thought into it and just winging it as they go, or they're really just that good/fast at it.
Just giving you a heads up that work on the actual writing of my novel is currently on hold so that I can solidify more of the world settings (especially the human countries) and on top of really needing to finally get back to translating my project, I probably won't be working on chapter content until some time after I finish translating volume 1 of Seirei Gensouki. I know you've probably been waiting for a while now, but I was actually rushing too much when I started writing and didn't make enough preparations for the actual writing process, which has been causing a lot of issues when it came to writing chapter 3.
Nah, my party only got like this because of power creep. The power balance changed massively when sega introduced version 2, kizuna no shin tairiku. Archers went from support class to being on par with warriors because guns.
That aside, once you get past the first major wall in the game (mainly getting your rank high enough to fill your party of all gold characters and leveling them properly), the game gets easy enough with the exception of certain fights. The ability unlock quest for Fina (heroine) is absurdly hard (the quest itself is labeled lv 80) and next to nobody has cleared it without having to revive their party mid-battle at least once.
And well...I just have lots of time to use in my current situation, so I gotta fill the days somehow. Haven't been able to get to work on translating Seirei Gensouki for a while though because I've had to deal with other things first....not to mention recently my previously thought to have been dead desire to be a novelist has revived, so I've also been taking time to work on my own story here and there.
I auto-battle most of the time outside of hard event battles nowadays because I've cleared everything already and my characters are strong enough to handle the daily training battles without me having to pay attention.
Oh, and I don't even use my strongest party most of the time either. Only for the extremely hard event battles or quests. Strongest party is the 4 main party members lv 80 then my sub party gives me a total of +20% atk +15% def, and movement speed buff. Oh, and let's not forget about the kizuna system we have in JP version that makes it so that my characters have atk and/or HP at 10k+ before even including the sub party buffs. This results in 2k dmg per normal attack. I even have a character that does 4k crits.
Chain Chronicle doesn't even take up that much time though? Unless we have certain types of events, but those don't happen very often and I don't always go all the way through them. Normally it doesn't even take up 10 mins per day. Besides, once you get to a certain level, most battles you can just hit the auto button and you just leave it to do its thing.