Checking where the admin tool is gone, yes, it is removed from 2022 release wave 2
The second wave of the 2022 release will see the removal of the Business Central Server Administration tool for on-premises installations (version 21.0). Please use the Business Central Administration Shell instead.
Soon license files in with extension. Business Central on-premises will no longer support the flf format.
Going ahead importing license files in with extension. flf format will not be supported in Business Central 2023 release wave 1. Start using the newer. bclicense format instead. The format remains supported for older business central versions.
Promoted action groups behaviour
Modern Action Bar on Feature Management page is set to Enabled, promoted actions, which are defined inside a group whose visibility is set to false will no longer be visible on the promoted side of the action bar. This pattern in your apps is easier to spot with the help of a specific code analysis rule in the UICop analyzer (AW0013).
There are more feature which enables business central smooth performance ,easy to use actions, You can check rest of deprecated features here deprecated-features-platform