It isn't canon and nothing in this series is going to be considered the defacto record of what happened in the 2nd age.
And that is because they don't have the rights to tell the 'defacto' story of the second age.
This is the confusion that Amazon themselves have promoted through their marketing and that is the problem.
Which says that the Tolkien estate allowed them to use the words LOTR and Rings of Power aiding the confusion.
The only thing they have the rights to are some characters and places from Tolkien in the appendices.
Otherwise, everything else is simply Amazon's own made up story and irrelevant to the actual lore of the legendarium.
Sounds like you just cannot accept that reality.