I use docbook for my ebook workflow, so I have a good deal of insight into this question.
Employment-wise, I haven't seen a lot of demand for docbook, though occasionally it is called for in open-source documentation. A lot of programmers know about it, and tech pubs know about it. I'm guessing that DITA is somewhat more popular in tech writing circles. ...
I was able to work around the issue as follows:
$ pandoc -S -o mybook.markdown mybook.tex
$ pandoc -S -o mybook.epub --epub-cover-image=images/my_cover.png title.txt mybook.markdown
By converting the LaTeX file to markdown, the second pandoc command was able to apply the Title, Author and Date information in title.txt to the epub file.
Short answer: no. Having to learn something complex like this will simply delay actual writing. Try a very simple editor. An office product, or text editor such as VSCode which is quite nice. I suggest writing using Markdown, and then generate epub and pdf using Pandoc. Those tools take a day or two to figure out. The Markdown Extra syntax is nice, supports ...