I was in a conversation with some friends yesterday and we were literally talking about this topic. He was lamenting how his interview was all about algorithms, structures, design patterns, data modeling and more but after getting the job, he really doesn't use these things more often but rather does the actual work.
I really don't think it's a bad idea to use other packages and mix them together to achieve your goals, those packages were built to simplify the process and make things faster. We have lots of JavaScript libraries and packages than we had when the language started and I can imagine how JavaScript development would have been without these packages.
I still have friends who still prefer to write their own package and loathe relying on other packages (The so-called "10X"), it's more of a personal preference but using other packages daily to do your actual work is not a bad idea and shouldn't make you feel less of a dev.
If you feel "less of a dev" because of this, try doing some personal projects that'll require fewer packages and you writing more "devy" code and let's see how it goes, in the long run, you're doing the dev work and still using packages at work.