I think you’re downplaying Muller here.
Over a 5-year period from 1969 he was named one of the top 3 players in the world in 4/5 seasons, winning it once. He was in the team of the tournament in the 1970 WC and 1972 Euros. He wasn’t just rated as this outrageous goal scorer whose record stands the test of time, he was an elite player and recognised as such at the time.
And it’s not like this era prioritised goals above all else. When he finished as a Ballon d’Or runner up in 1972, having scored 50 goals in 48 games, Beckenbauer was voted ahead of him. Ostensibly a defender and a player admired for his elegance and leadership over any blunt measures of productivity. Muller was considered right alongside him In the early 70s.
Compare that to Zidane who over a 5-year period from 1997 was named one of the top 3 players in 3/5 seasons, winning it once. 3rd in 1997, 1st in 1998, 2nd in 2000. And it’s not like he had stronger competition. Muller was placed alongside Cruyff, Beckenbauer, Best, Rivera, Riva, Mazzola, Netzer and Zoff. Zidane was placed anlongside Ronaldo, Rivaldo, Figo, Shevchenko, Beckham, Šuker, Mijatović.
There’s only no doubt that Zidane is a better player because Muller has been stigmatised and caricatured even by people who think they’re defending his name. The idea that he was just a poacher is really silly.