>There's a problem to be solved, so let's attempt to solve it or at least compromise in good faith

Of course saying "I validate that you are feeling upset" is going to come across as patronizing and insincere. But I don't think that's because they validated your feelings. It's because of the way the validation is said.

Part of what makes a conversation good faith is hearing out what the other person is saying and agreeing where there is common ground to build from. That necessarily includes confirming the pain points each person is feeling.