What's your opinion on building a product that already has numerous 'big players' in the market?

If you can find a profitable niche to target, it can still work out. With the previous startup I worked at, we were developing a project management tool. The space is very crowded with new competitors popping up constantly. Once we tapped into the telco industry is when we managed to find our space and scale from the local market to US, UK and the EU markets.

offer something unique it doesn't have, improve on what it currently has, and undercut pricing (if any) significantly 🤣😂

I don't know how big 'big players' are but big companies have a lot of niche projects and customers that can get lost and overlooked. I think it's worth using whatever your competitors use (and get other people willing to give feedback to do the same) and find out what you find frustrating or missing in the UX.

What's your differentiator? Every incumbent can be displaced. Maybe the industry itself can be changed. What's the smallest profitable white space you can start with? What's a new way to solve the old problem?

It can take place only if you can offer new unique features to the users that big players don't have. But your product should be really unique, some kind of innovation. You have to do detailed market research, maybe even do an interview with your potential clients. And maybe then you'll have a chance to succeed. There are a lot of real-life cases on your issue. For example, Lunacy. It's a graphic design app like Sketch, but unlike Sketch it can be used on Mac, Windows and Linux. And that’s the Lunacy’s unique feature. Or let's take another example, Dropbox and Google Drive. Dropbox quickly gained on Google in terms of revenue and market share due to the launch of its own file storage platform. And that’s worked. You can read more about it here.