I think people are really overstating how preps affect the game for beginners. I hardly touched preps when I was learning. I didn't know how to unlock them, I didn't know what they did, and I didn't know how to leverage them when I found them. My most used prep for the longest time was the simple health pendant. I didn't touch gods at all because they were complicated and usually worse than nothing at my level knowledge. This approach got me through all of the sub-Vicious content. After hearing about how preps let you auto-win I prepped someone to the gills and sent him into Namtar's Liar and almost immediately run back out.
Most of my intermediate gameplay was picking random runs (we didn't have PQI back then) and just screwing around. I found simple combinations that worked, "If I roll a Halfling, then Trisword is really good." But there was never a point where I felt that I had to use prep combo xyz and only this or I would never progress or never have fun.
Even now, I mostly use preps to experiment with specific strategies or as a way mitigate irritating circumstances (eg things like Soul Orb, Burn Salve, Fortitude). For all of the talk about how you are forced into using the power potions and Dragonshield, I probably use those things maybe 10% of the time.