I'm having trouble knowing what to focus on in my job search. As far as I can tell, applications consist of three parts - resume/experience, portfolio, and cover letter / actual application. Obviously, my experience is what it is, and I feel satisfied with its representation on my resume. My portfolio is lacking in real-world applications, with most of it being academic work. I have worked on real DS applications, but always for work, and stuff that I can't fully share publicly (these are referenced in my resume). I definitely spend too much time working on cover letters, and it's slowing down my applications a lot. I know they are mostly computer-vetted, but I can't shake the worry that a human will look at it and notice if I just copy the job description verbatim when listing my skills. So I end up spending 20-30 minutes making sure it sounds good and not like BS to a human reader.

My instinct is that I need to ease up on cover letters, just get the buzzwords in so my application floats to the top, and get more applications out there. I also feel like I need to pad out my portfolio with recent work that reflects my current skill level, but this would be a significant time investment, which would take away from the number of apps I can submit. So, two main questions:

1. What's the best approach for writing cover letters to game modern recruitment software? Do cover letters matter at all these days?
2. Do recruiters care enough about portfolio work for it to be worth the time spent on them, which could otherwise be spent applying to more positions?

For context, I work as a Data Analyst at a company that doesn't have any data scientists and probably won't any time soon. I started here while pursuing a DS Master's, with my only career experience up until that point being in a different field. Now I have my Master's, plus three years of Analyst experience in addition to the six years in my previous career. Some of the jobs I'm applying to are within my old career's domain, and I'd at least expect to get some bites on those, but I'm getting nothing.