I feel like alot of noobs try to look up Ronaldinho and Zidanes stats and then argue that they werent that good. They dont realize that in the 2000s teams would have like 60 goals a season with like 70 something points to win leagues. Back then games were more defensive because a win used to be 2 points in the early 90s, and teams were slowly adjusting out of the mindset that draws and wins arent that distinguishable. In the 2010s the top teams were scoring 80-100 goals and getting 90 points in the league. Even in serie a the second place teams were getting 80+ goals. I definetly could see a young Ronaldinho lighting it up in the modern era, or a young Zidane doing even better than he was.
Shearer is the PLs highest goal scorer and that record will take some bearing. Assuming Haaland remains and maintains his incredible goal scoring feats, he’ll probably best that. Shearer however did that in an era before sports science, data science and world class setups - much harder on a potato field
However he also did it in an era of much worse defending and tactical play. The fitness argument works both ways too as most defenders back in the day were bumbling oafs who were tall and stuck the boot in.
These discussions are always invariably pointless. The game has changed so much that it’s impossible to tell how players from previous eras would adapt.