Building Yocto for Rock Pi 4B

How should I build Yocto for Rock Pi 4B?
Manual https://wiki.radxa.com/Yocto-layer-for-radxa-boards says “Select Release Dunfell” and then " Select Release Zeus". Is Zeus better than Dunfell?
What is state of branch Dunfell?
And what about more recent LTS Kirkstone?

If I have select Dunfell then where should I get meta-radxa?
And what is difference between repositories nishantpoorswani and Radxa ?

What is recommended distribution of Linux? Bitbake says “Host distribution “ubuntu-20.04” has not been validated with this version of the build system”

I’ve try Zeus, Radxa, Dunfell and got

WARNING: .../yocto/poky/build/../meta-radxa/recipes-connectivity/bluetooth/bluetooth-rockpi-s.bb: Unable to get checksum for bluetooth-rockpi-s SRC_URI entry install-module-hci-uart.service: file could not be found
WARNING: .../yocto/poky/build/../meta-radxa/recipes-connectivity/bluetooth/bluetooth-rockpi-s.bb: Unable to get checksum for bluetooth-rockpi-s SRC_URI entry rtl8723ds-btfw-load.service: file could not be found
WARNING: .../yocto/poky/build/../meta-radxa/recipes-connectivity/bluetooth/bluetooth-rockpi-s.bb: Unable to get checksum for bluetooth-rockpi-s SRC_URI entry install_module_hci_uart: file could not be found
WARNING: .../yocto/poky/build/../meta-radxa/recipes-connectivity/bluetooth/bluetooth-rockpi-e.bb: Unable to get checksum for bluetooth-rockpi-e SRC_URI entry blacklist-bt.conf: file could not be found