I bought the game initially in July 2017, have put about 235 hours in according to my latest scoresheet and have 88% lore and 86% gallery. It takes a long time to find everything (GJ's scoresheets say he's spent 900+ hours in comparison) and some of them I learned how to get by being spoiled from watching Twitch streams which I will list in the spoiler tag along with a little information about the things you don't understand.
mtf's combat hacker run is one of the first streams I watched.
LuckyLuckLuc showed me the Archives event. It is quite rare though you can cheat by looking at the save file to see if you'll get it on any given run and hence whether to bother with Archives. But just keep going to Archives and eventually you should get it.
Valguris's stream shows how to deal with golems and also LOTS of extended end game spoilers. There is a warning to that effect before the last segment of it, the first recording is the one that shows golems.
Basically you just have to get good at combat, there is no secret shortcut to being good, or if there is I don't know it. Take your time and think, learn how the mechanics work, practice and don't rush past the early levels.
It's fairly easy for me now to get past the early levels of Factory, deceptively easy in that you can do so without having a build that can survive the end game. The best players seem to have a very good idea of exactly how far they can push their luck before escaping to the next level.
I have a list of what I think all the endings are from studying scoresheets, but I have only gotten what I think are the three easiest ones.
