EnderDragon#getDragonBattle() no longer returns the dragon battle, when the dragon was summoned by command or any other plugin.
It only returns null.
Dragons that are spawned by placing four crystals on the portal have the DragonBattle set. In this case is is returned correctly!

Getting the dragon battle from the world by World#getEnderDragonBattle() always returns the correct battle.

see JavaDocs: https://hub.spigotmc.org/javadocs/spigot/org/bukkit/entity/EnderDragon.html#getDragonBattle()
The text has not changed from 1.19.x !
So the function should still be the same. (but is not...)