TL;DR. Too much personal fluff and no meat. Nobody cares about your hobbies unless they're directly relevant to the position.
Overly general. You haven't differentiated yourself enough from others applying to the same position.
These kind of cover letters/emails should be highly specific to the company you're applying to. It should answer the HR manager's primary question: Is this applicant the best person to help the company achieve its goals?
Find out from the job description what you're being hired to do, and provide examples of things you've done in the past that are similar. Help the manager imagine how you could apply your experience and talent to that position. And do it quickly, since they're reviewing hundreds of these a day and will spend less than 30 seconds on yours.
Customizing your cover letters in this way is definitely more effort and more time consuming, which means that 99% of applicants won't do it. Be the 1% that stands out.
Finally, the HR filter sucks. Find the actual team managers/members and reach out to them instead. Referrals, even if cold, are better than nothing.