What are the development prospects of the engineering plastics industry?

My undergraduate and master's degrees are polymer majors. I am about to work. I have signed a new product development position in an auto parts company. Near graduation, I got an offer from an engineering plastics modification company for research and development of a position, and I have something to do. I have always wanted to work in the plastics industry. The company is mainly engaged in the research and development and sales of PP, PC/ABS and other modified plastics, with a scale of about 100 people.
I personally think that the current engineering plastics market is very large, but there are many modification companies with sufficient production capacity and fierce competition in R&D and sales. The position given by this plastics company is R&D, but it plans to do R&D for a few years and then sell it (I heard that doing sales can quickly buy a house, haha). Regarding the industry prospects and career planning, I would like to hear the views of the predecessors, and I hope you can give me advice.