Opinion on Popper: it's not good and the number of swear words in my answer depends on the company.
Falsifiability has it's uses but imo only to the extent that it's compatible with dialectical and historical materialism. In Popper's hands it is not.
Popper seems to have been motivated by anti-communism/Marxism as much as anything else. His work should be evaluated in this light. He didn't necessarily start with sound principles and follow the logic or start by asking scientists how they did science and deriving a theory therefrom. He was starting with the question, How can I show that the Marxists are wrong? He doesn't necessarily make this clear. This is… ironic, considering what he's known for.
This doesn't really answer your question as I don't feel overly qualified to give a fuller, direct answer but maybe it will provide some food for thought when hearing other answers or looking him up.
Maurice Cornforth wrote a scathing critique of Popper in The Open Philosophy and the Open Society. If you search on here for Cornforth and put redtea as the user, you'll find some quotes that I previously posted. The quotes focus on formal logic and Popper's misunderstanding of the dialectical materialist conception of contradiction (rather than falsifiability).