Finding real problems to solve can be difficult.
You have to find something that is big enough for you and your team to invest time into but small enough that the market doesn't already have many established solutions.
There are 4 types of products based on the problem they solve,
Almost all great startups lie in the fourth category. You have to solve a big problem for a small number of people. Facebook, even though it's definitely a type 1 (big problem - big market), it started out as a strong type 4. Facebook solved a big problem for a handful of students at Harvard University.
When you look at a big problem for a large number of people, chances are that there are a dozen products filling that specific need and rather well. You will need to go against the competition that has been in the market for many years and has all the edge over your product.
If it's a small problem for a large number of people, there is probably a small number of products in the space, but they are unlikely to be as good because it's not their primary focus.
Solving a small problem for a small number of people is not even worth discussing. There's just no market for such a product.
Solving a big problem for a small number of people is ideal for a new product. But, catering to a small number of people does mean a smaller market. The key is finding a small but growing market that has at least one established competitor.
Competition is a great indicator of your product being viable. It means there's a broader need for the product in the market no matter how small it may exist as far as numbers go. In other words, finding competition that speaks to a shared problem makes your idea more valid.
Above all, find a small market that you understand, a problem you know exists, and a solution that you'll deliver passionately.