You have not provided any system information - but judging from your profile you are using Xfce desktop on a AMD system with AMD gpu using linux 6.1.
Since the greeter provides a graphical login - it is dependend on the GPU drivers - provided by the kernel.
Then you will have synced the latest LTS kernel - which appears to bring with it a regression which causes some AMD GPUs to fail.
On several occasions the solution was to use runlevel 3 and sync the latest stable kernel
Perhaps your system is affected by this
sudo mhwd-kernel -i linux64