Have you removed the old image and the old container? To do it run docker stop pihole then run docker system prune -f That last command will delete everything not being used.
I’m running this with the latest Pihole beta 5.0 on Beelink GT1 Ultimate running on latest CoreELEC nightly.
After this run your docker run/create command replacing the line “pihole/pihole:latest” with pihole/pihole:beta-v5.0-arm64 will download that image and create the new container.
Hope this works for you.