I may add to the title "but you should embrace it."
Indeed, even your brand new feature will be code legacy in a few months :)
Note that it does not mean you cannot update old code with new patterns, as long as it makes sense for the business.
I know what you're probably thinking. It's unlikely if you test your code correctly.
Untested code is considered as pure evil by an extensive range of developers.
Of course, you should test your code, but even with the best tools and several layers of automated tests and validations, unexpected bugs may still happen.
At the end of the day, you write your own tests.
IMHO, code quality means those bugs remain rare, and you're able to fix them quickly when it happens (e.g., rollback + hotfix).
In a nutshell, test your code, but don't get a false impression of safety.
What can go wrong?
You may fail at some point. OMG, and so what?
Remember, nobody cares. More seriously, most people won't blame you, except if you repeat the same mistakes again and again.
So fail, learn, succeed, repeat...
There are memes for that, and it's sometimes called SODD, which means "Stack Overflow Driven Development."
Of course, it's bad, especially if you copy/paste solutions without understanding what it does.
However, most beginners do that (and they're not the only ones).
The good news is that it often works, as there are common issues and vendors in this industry.
The bad news is that "non-contextualized" solutions can introduce unexpected bugs in your application.
There are various threats to your mental health, starting with your own ego.
This one is very hard to catch, because you're probably humble, with a good mindset, but you still have an ego.
"Egoless" does not mean "no ego," like "serverless" does not mean there's no server behind the scene. You just don't see it.
Just admit it, and don't let it speak too loud or beat you up.
I'm definitely not saying nobody can learn this job without buying technical books.
Although, it's a great investment in my experience, as the quality is usually high.
People are very different. There's no magic formula.
Most technical writers share their tips in the hope it will be useful for others. Nothing more.
Besides, this industry is constantly changing.
It's sometimes skipped, but common values form the bedrock of a company.
Technical roles are impacted just as other roles.