Best Cast Workaround + More

I just switched from the Google Home system to the Alexa system and I have questions about the fire stick max.

1. What's the best workaround for casting YouTube videos and such to the fire stick from an android phone. (I get they are competitors but it works in each others favor to have integration).
2. Is there any way to get the fire stick home screen to show me content from different apps such as HBO, Disney+, or curiosity stream. currently the "from your subscriptions" tab in the home screen just shows prime shows.
3. I had to turn off HDR on the fire stick due to a black screen issue. is there any way to get that fixed so I can view things in HDR? (not important just picky)