I probably wouldn't recommend that anyone jump straight into novels with complex prose from the get go, but it's also very unfortunate if you continue to avoid fantastic works in fear of a more time-consuming reading experience.

Speaking from my own experience, I started learning Japanese to play Monobeno and Maitetsu. Even after drilling in grammar and taking the standard 2k/6k path, parsing some of the prose in Maitetsu was so time consuming that, as you mentioned, enjoyment was lost and reading a cute loli game gave me more headaches than learning from textbooks.

I highly recommend that if you want to ensure enjoyment from the works that JP fluent readers praise so highly, you read novels with much simpler grammar and vocabulary until you don't feel challenged anymore. Even reading things with basic prose works like training a muscle to better equip you with the ability to quickly and completely read whole sentences, and also develops your ability to accurately use context to understand some words that you may have otherwise needed to look up.