I'd say check out the work of William Shotts at
https://linuxcommand.org/ His book, "The Linux Command Line" is free for downloading, and there are lots of references to style guides, good practices, and bash templates in the book.
There is also a shorter, HTML version at the same site: https://linuxcommand.org/lc3_learning_the_shell.php
I'm trying to get a little proficiency in all this, and just yesterday I went through the "Further Reading" sections at the end of each chapter, and captured all the likely URLs for further investigation.
One that looks really good is Dylan Araps' "Pure Bash Bible" ( See https://github.com/dylanaraps/pure-bash-bible ) Confession: I found a PDF copy at Libgen, but don't tell anyone. This and the Shotts book have also been thoroughly discussed on Hacker News in the past. (I.e., search on the two titles and you'll probably get all the opinions that you can stand, plus maybe some more hints.)
Bash is profoundly weird, but if/when you can make it work, it's slick.
