Boris FX has posted an in-depth tutorial on how to set up Chroma Key (green screen) to get the best results.
I highly recommend anyone learning how to make "green screen" videos, to read this article. borisfx.com/blog/howto-setup-chroma-key-for-success/
Remember to turn everything off at least once a week, including your brain, then sit somewhere quiet and just chill out.
Unplugging is the best way to find solutions to your problems. If you would like to share some love, post a customer testimonial or make a donation.
Peace