Earlier quoted context omitted.
R2 is an insane value proposition. We calculated the cost of moving HLS video delivery to it and unless you are delivering a huge amount of traffic, the costs are far lower. Highly recommend you consider it, assuming you are willing/able to handle appropriate transcoding yourself (if not, Cloudflare has it's Stream product)
What is 'appropriate transcoding'?
Typically this takes the form of creating "renditions" of the source video at lower resolutions, but you'll have to decode and re-encode the video to do that, hence transcoding.
Pretty much all video you watch online is delivered using an adaptive bitrate technology like HLS or DASH. That's what allows the video to automatically reduce its resolution if your network can't handle streaming the video without buffering.