Web developers make huge mistakes when bringing best practices in web development to WordPress. This confusion results from not respecting WordPress as a full application and instead seeing it as a web framework akin to something like Laravel. Specific WordPress training and experience is essential for development teams to be successful working with WordPress.
Software engineers often look at WordPress with a disdain and develop an insatiable urge to fix all of its quirks and idiosyncrasies with their own custom project. Then sometime later these same developers find the urge to go rescue some other fumbling software project or chase the latest programming language and end up abandoning all the website owners who became dependent on their software. Rinse and repeat into a cycle of frustrated business owners.
Front-end and back-end development skills are not a substitute for specific training in WordPress. Even the best developers will need to retrain their skills and gain experience and intimately get to know how WordPress works. Underestimation of what it takes to work on a WordPress project is this cause of many late night coding sessions scrambling around support forums trying to fix a critical site error or meet an impending deadline.