Plasma Bigscreen has been disabled on Edge until Plasma 6.1 releases. It remains available on v23.12. This was done due to that the latest release of Plasma Bigscreen isn't compatible with Plasma 6.0.
If you have an existing installation of postmarketOS Edge with Plasma Bigscreen, be careful running # apk upgrade -a as it may result in the user interface being removed.
For now, the only options for users wishing to continue using Plasma Bigscreen until it has been added back are to patiently wait and be careful with upgrades (not recommended as you may miss out on security updates) or switch to v23.12 (also not recommended as we don't support downgrading from Edge to stable releases).
Related: !4883