Take advantage of the fact that everything is connected to everything. You know one of those programming blog posts you're already reading? You know how there's that link you didn't follow because it was a reference to a show you've never heard of or something? Follow it. You know that article you read that yells something or other about what somebody else said, and has you nodding your head vigorously about how stupid that person must be, but, suspiciously, doesn't link to the original content, or worse, fails to even quote it? Go seek out the original content. Then follow a couple of
those links. You get linked to a YouTube video... actually look at the "similar video" links that YouTube spits out, try out a couple that you don't know what they are. (This works surprisingly well for "real content"; linkbait viral videos will of course produce just more linkbait viral videos but when you hit the good stuff the first few links are often also quite good.)
And if you've got some spare income, be willing to start buying a book here or there related to what you find.
I mean, if you have the desire and the stamina to make one of the big leaps here, do not let me stop you; those are good too. But you can incrementally escape from your current filter bubble, too, by growing it. There is no such thing as not being in one, because you have to have filters, it is literally impossible not to, so there's not much point in angsting about it, but it is possible to upgrade your bubble.