I am trying to get my videos to stream properly, they are too slow now. My videos are all at one bitrate & I am looking to get these videos so they do not buffer and load fast, what would be my best option please?
Roku doesn't support RTMP. The context where you would see that in relationship to Roku is if you are broadcasting a live stream, you would usually RTMP to a server that would convert the video to HLS and deliver that to Roku.
I haven't worked with cloudfront directly myself, but I am pretty sure cloudfront _is_ a cache, it may have some other caching features you can enable or disable, probably has an expiration timeout you can set - how long the video stays in the cache before it is erased.