However, being an introvert, made me doubt whether I can make any career progress in startups at all. So far I see that the company is ruled by sales, marketing and investors. You are extrovert, talk better and "make more friends and impress people" you are more successful. You are introvert and mind your own business, you are in trouble.
I appreciate if anyone could share their thoughts and experiences on this.
That's not really what an introvert is.
I'd recommend reading Susan Cains book "Quiet" for a really deep dive on the psychology of introverts, extroverts and ambiverts, but in a nutshell it's about how you recover from social situations compared to being alone. Introverts need time away from others to reenergise. Extroverts need time among other people to reenergise. Ambiverts are those rare people who get energised by both.
To that end, the answer to your question is really to make sure you block out time to be on your own in order to recover after being in social situations.
If you genuinely don't like social situations that's something else. It could be shyness, anti-socialness or a form of social anxiety. What strategy you use to deal with those things is a bit more complicated and very personal to you.