Should I keep investing on my blog or should I focus on something else

Your writing seems "good enough", and your images are very good especially if they are AI generated. However, your titles aren't very eye catching. I scrolled past all the article titles and none of them really motivated me to click on them. I finally chose a few to speed read and yeah, the quality is fine. You need to pick a focus though. Develop a narrower niche where you are THE MOST interesting of ONE type of article, not a middling mixture of many types of articles. At a glance it seems you cover book reviews, manager advice, programmer advice and historical stuff. No offense, but being the best at any of those subjects is tough, but being the best at all of them is probably humanly impossible. Don't give up, just concentrate your efforts on one target until you get traction. Just my two cents as a random internet stranger though.