ok, here are some tips, trust me I'm good, I've reached endless mode in every run for the past 7 runs, I consistently reach floor 30 and I've reached floor 51 before dying to an unfortunate event with the grasshopper which forced my boost die to be glass.
Here are some things that I do to reach such floors, you might not like them but I believe them to be the right choice:
1. Thin to Win, having a lot of dices might be nice and make you feel powerful, but having only 5 dices increases the consistency of your build a lot. Always being able to know what you have is really good.
2. ALWAYS TAKE THE SPIDER, the spider asks you 3 questions, if you can answer them correctly it'll give you broken dices like a "basic block and heal die", get one of these dices and build around them.
3. Don't Use Terrain Dices, there dices might be good for the early phases, but I've learned that in a situation where weak attacks deal 5 damage Terrain are too slow for the situation.
4. Always Max heal, before finishing a fight always heal to full, it is way better to get the "increase max hp" option that the "heal to full" option as the fist one increases your Max HP permanently and increases even your shield cap-
5. Avoid Eternal and maybe avoid heavy, this dices might be powerful and might be OP with grow, but if you have enough hollow and you have followed point 1, then the lower numbers on the eternal dices will make a difference.
I hope to have given some good tips, Have fun :)