RS
Aside from the lack of senior support, this article just sounds like "I quit my first real job in dev because I have opinions, and the company doesn't align with them." This isn't your product, so your individual opinions only carry 1/nth of the weight in relation to every other dev there. There is nothing wrong with using NextJS as a plain React app setup, their routing solution alone is more than enough to opt into using it over React/React-Router. Not to mention the other bundling and building tools not provided out of the box with React alone. You had an opportunity to grow and use your voice from within the company to help lift them out of the tech debt they had over time, yet you chose to quit.