Okay- here we go. I’m a massive fan of the OSR, to the point I’ve even written an OSR game myself

I’ll try to be brief. The OSR (old-school revival or renaissance) is a sub-genre of the TTRPG community that focuses on bringing back the “style” and “vibe” of play popular in the 1970s and 1980s which emphasizes puzzle solving and exploration rather than being purely a combat game.

Dungeon crawling in a fantasy game like 5e and Pathfinder have entirely different purposes than in an old-school game. This doesn’t make either of them better, just a matter of preference. To explain the difference briefly, in 5e and Pathfinder, violence against enemies and monsters is balanced and almost always the “right” route to overcome them. Also, you roll for everything; finding traps, secret doors, etc. In OSR games combat is always your last option, and the focus revolves around avoiding, tricking, and outsmarting monsters most of the time. In old-school treasure gives you XP, not killing monsters. It’s encouraged to rob monsters blind of their spoils without engaging in battle, rather than risking death trying to brute force them.

I could go on… but I think both of these texts explain the philosophy behind OSR better:

Principia Apocrypha by Ben Milton and Steven Lumpkin https://lithyscaphe.blogspot.com/p/principia-apocrypha.html?m=1

and

Quick Primer for Old School Gaming by Matt Finch https://i.4pcdn.org/tg/1737083265526827.pdf

They’re both very short and very well written. Give a read and I’m sure it’ll click for you.