"We chat" is just to combination of multiple apps. There are many apps with similar concepts like messenger apps. You hardly find any uniqueness in Skype, WhatsApp, Viber and signal etc. but all are successful and have billions of users. They all trying to solve same problem with similar solutions. The only difference you find is UI design and some minor things. Similarly, Udemy, LinkedIn learning, Lynda and Edx offers almost same services. Do we need to find problem or can we solve same problem which is being resolved by competitors?
Yes. An idea's utility is entirely based on its ability to actually solve a problem and a successful idea creates value in the process.
Digging deeper into your question. More than one person can solve the same problem, the challenge is who can add more value. Remember big markets where you have mutilpel players, may exist for many reasons like
1. Market coverage
2. Market access
3. Unique value-adds
4. Time to market
5. Stability and availability
One of the challenges in our education and society where never been told we are "problem solvers". The better, the faster, and more value your ability to add when solving a problem the more valuable you become.