I think it is a wrong question to ask. You should not be brainstorming to come up with a problem to solve. Because you will have no idea if this problem is valuable enough.
A better approach would be to find a customer you would like to serve and just figure out ways of having meaningful conversations with them. Then find out what type of conversations your customers find valuable. And us it as a hints about the valuable unsolved problems in your customers life.
I agree, its really hard to find genuine advice. I go one step further to say any advice no matter how well intentioned has a very low value for the person receiving it.
Here are my chief reason.
When someone gives you an advice that solves your problem, they robe you of the skills need to solve such problems in the future. And if you succeed all the credit will go to your advisor. However, in case of a failure it's you who would fail.