Okay, let's see... This might be a long post. So, I'll focus on things that should be easily available and for free.

YouTube has plenty of movies and shows in Polish. It seems that the algorithm doesn't care as much about Polish content, especially if it's older. Some classic movies are available in great quality for free too (e.g., Studio Filmowe Tor).

Major issue might be that intermediate and advanced content (movies for grownups) may have more subtitle options than beginner content (kids movies). One exception I thought of is the bizarre Akademia Pana Kleksa that I watched with some friends recently. I'm sure there's more. A way to avoid the sub problem in kid content would be to look for Polish dubs and subs of Netflix kids content, e.g. Steven Universe and such.

If you don't care that much about subtitles, you can go back to roaming for free on YouTube. I just looked for Moomins (Muminki) with a Polish dub and there seems to be plenty of episodes available. If you'd like to try something really old-school, there's also Miś Uszatek, Przygody Kota Filemona and Ferdynand Wspaniały. There's also some old live-action content like Tik Tak, an old kids variety show.

One thing that people might not know about is that -- in addition to subs and dubs -- there's also a weird third option. It's called a LEKTOR. In practice, it's a single person reading through the entire dialogue of the movie/show while the original audio is playing in the background. In terms of free YouTube content it leads to a bizarre situation where you can easily find full US movies with a lektor, which I guess is too confusing for the algorithm. I was just able to find full uploads of Pulp Fiction and Se7en right on YouTube.

While it's a bizarre experience for someone who is not used to it, lektorki and lektorzy usually have amazing enunciation/pronunciation that might be great to listen to if you're getting used to the new sounds Polish has to offer. Finding content you like and/or are familiar with might be an added bonus.