why i dont cane change from dev to beta chanel

Hi yurahell 

Microsoft only made this possible when beta and dev versions. were the same, currently lowering the Insider channel to Beta -> you need to do a clean installation of Windows that will remove everything, personal files and applications too.

Lowering the Dev channel. - to Beta without a clean installation of Windows - is available!!! - Microsoft Tech Community

You can download the stable version of Windows10 or Win11

Or download from the Beta ISO channel and perform a clean installation, if in the settings you check , to leave personal files there will be an error, you need to remove everything to reinstall the version already Beta

https://docs.microsoft.com/en-us/windows-insider/ISOs#clean-installation-with-a-windows-insider-preview-iso

https://docs.microsoft.com/en-us/windows-insider/ISOs#clean-installation-with-a-windows-10-iso