I feel like I should have gotten this concept a while ago... thank you for informing me.

Well, the person I was replying to was talking about light in general, not a single photon. This is something I only have basic knowledge about.

Interactions with stuff does change it in one way or another. The way the sky is blue is light interacting with air, and tinted glass changes the light going through it. I don't know the mechanics, but that's a change in the photons without changing total speed.

One thing to remember with photons is that while speed is consistent, intensity isn't.

Assuming there isn't delays after initial release....

Or you could just have a healthy diet to get everything you need instead of funding unregulated supplements

100%, with streaming software