Been in the game for over 35 years. The whole hiring system is stilted, inefficient, intimidating, mono directional, subjective, and don't even guarantee you'll have a good fit in your organization.
Cover letters are just pompous outdated redundant form letters. more than 50% of hiring managers don't read them either out a lack of time or simply they can't tell the difference between one or the other. In some case, for dead end jobs, writing a great cover letter might work against your chances of getting hired
I always went against the convoluted system, with my bosses initially questioning my so called "unsophisticated" non systematic hiring practices. What few realized, even when i was at a VP level, is that i spent enormous time consuming every line of each resumes sent, before even daring to jump on the bandwagon of a good one page sales pitch. Turnover was low in our organization and most people fit well . there is no secret except to spend the merited time for each resume
Now let me tell you about all the negatives on the hiring process...