LUM is a legacy Groovy app and all Groovy apps stopped being supported in January 2023. You can no longer use LUM.
There is no native ST capability for time based user lock codes and Rboy has not released a replacement for LUM in the new architecture.
Some people are using other third party solutions that support time based codes like Seam or lockmanager.io. Others are using Sharptools to add and delete codes at specific times to emulate the behavior formerly in LUM.
As far as notifications go, you should be receiving ST app messages if you have Smart Lock Guest Access (SLGA) installed. For SMS notifications, you can use ST Routines to create customized texts for specific users, if you have the paid driver that exposes the lock/unlock code slot name. You can use a 3rd party rules engine like Sharptools and still send customized messages if you have their premium level that allows access to event data via variables.