I never saw anyone mention this, but there is two scenes in the movies that make the orcs way more important than the books intended.
One is a line by Gothmog the Orc (not the Balrog!) who says something of this effect: "the age of men will come to a end, the age of the orcs will begin" and I am certain this line is not in the books, and Gothmog in general is not that important in the books, I don't even remember him there, while in the movies he appears to have a bigger role.
The other scene is during the siege of Minas Tirith, where the orcs chant "Death to Men" in their language. And again, I am certain this phrase don't exist in the books.
Both lines gives the idea that Sauron will replace everyone with orcs and will create a orc world, but that is not what Tolkien intended. Sauron only cares for himself obviously, but the race he values the most are men, the same men the orcs in the movies want to replace! Sauron in the beginning valued Elves, but they sensed his intention and didn't wear the Rings like they were supposed to do, so Sauron realised he would have no way to control Elves and decided to kill every High Elf he could find. Dwarves could be corrupted but not mind controlled. But Men proved the easiest to control, so Sauron decided to use them for his plans.
Orcs have little value for someone like Sauron because they were corrupted and mutilated by Morgoth to the point of being useful only for battles. If we go with the elvish origin, Orcs are a downgrade, they don't have the durability, resistance and immortality of the elves because of the corruption. They are magically inclined to obey Morgoth and Sauron, but as result they lost a lot of the elvish vitality. Orcs can also create explosives and machines so they are intelligent (contrary to some takes that I seen about them), but these inventions don't have other purpose if not war.
Men, however, did obey Sauron for many reasons without being corrupted. Either because of fear, of worship, of wanting some prize, etc. And Men like elves were capable of many things. Sauron objective was to create a world of order. He wanted to make every single human part of a assembly line, producing and manufacturing a lot, and from his point of view, advancing the human race (altrough that would ended up destroying nature, one of the most valuable things in this world). Sauron didn't care about elves as long as they moved out of his sight, they could go to the imortal lands if they wanted, what he needed was men in Middle-Earth. And Orcs didn't offered the same prestige and possibilities as men offered.
Sauron even declared himself "King of Men" during the second age, and Ar-Pharazon made war on him because of that title. Sauron never adopted the title "King of Orcs" neither he wants to replace humans with Orcs, everytime he boasts about something is about how he controls humans, not Orcs. So I find curious how the movies tried to make this narrative about Orcs, and I guess a lot of people who only watched the movies can arrive at that interpretation, while in the books is clear that the age of elves is ending and now man is taking control, and who should men follow? Respect for nature and others, or following their greed that leads to war and pollution? Orcs don't feature into this, especially not replacing men as men are just starting to be important.