A few words on cover letters, why I love them, and why most are terrible:
They tell me a lot about a candidate's personality: how well they write, the extent to which they're aligned to our organization's work and values, the story arc of their career, and how they balance highlighting their expertise and value with a desire to learn new things.
Most people write them poorly, which also means that this is an area where you can really stand out. I can tell immediately if you are sending me the same letter you're sending to other hiring managers. Don't phone it in - it will hurt you.
So if you're applying for a job, spend a LOT of time here. If the application doesn't require a cover letter, submit one anyway. It's a great way to put some pts on the board and distinguish yourself.
P.S. Don't forget to tell me why you WANT the job not just why you think you're right for it. How will this role help you grow and why are you interesting in my org in particular? Many apps have an enthusiasm gap - you can address this and shine.
P.P.S If you're having a hard time articulating your excitement and alignment, maybe this isn't the job for you?