Especially with the rise of "ghost postings" so quantity over quality is greater than ever these days
Neither approach is good if you are looking for work in the tech sector without an existing referral network.
I suggest that you;
- Ditch the cover letter
- Have a bulleted summary of your skill set that lists every skill and every technology you are comfortable with right on the first page
- In your experience, when listing your past jobs and positions, include list of every technology you worked with during your time there
- Customize your resume for every position by simply highlighting or emboldening every instance of the key technologies they are looking for in your resume
Note: Sometimes, when highlighting skills you might notice that your resume undersells your experience with that particular technology. Go ahead and edit it. This happens a lot and it is ok to view your resume as a living document that is constantly being revised. Don't just set it and forget it.