Yes, you can do pip, you need to first expand the video to full screen, then tap the screen to bring up the on screen controls, and you should see a pip button in the upper left of the video.
Orion doesn’t have a dark mode that I’m aware of, though it mostly respects iOS dark mode (with annoying exceptions). Though with firefox extensions, you can install dark reader, or you can install the dark reader iOS app, to get dark mode on all websites.
Edit: I’m not certain that dark reader iOS app will work with orion. I don’t use the app, I use the firefox extension with orion.
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