I've had the best luck with a baffle and just putting it far from where the squirrels can jump. Though I do have a Squirrel Buster Feeder that's close to my window for my cat. For whatever reason, the birds don't like it as much, and it's kind of annoying because it doesn't do well with larger seed.
The same baffle I bought 15+ years ago remains undefeated to this day. Every once in a while - maybe once per year - a squirrel attempts to climb up the pole, but the baffle stymies them every time. As long as a squirrel can't jump from somewhere else, as they could in the AI-looking pic at the top of this article, a baffle works perfectly.
-bdd