This would be accessed either through the gamemode portals or a button found in the lobby, which would teleport you there.
Summary
The practice realm would be used for practice, as the name implies. Some features of the realm would include being able t change maps to suit what you want to practice and a changeable NPC that would help you gain information about a ability, practice combos, or aim.
Changeable maps
-either choose from the 3 existing ones or simple custom ones that are just a baseplate with no end, a baseplate with void, or a baseplate with a wall.
The NPC could have something similar to the custom menu that you would be able to edit its properties. The changeable properties would be in categories such as
Movement
-WASD (can choose multiple)
-Spam jumping
-Spam punching
-There would also be stuff like a button for moving towards the player/away (like robot)
You would be able to alter how long it does that thing through inputting how many seconds or if it does that thing permanently
You would be able to choose multiple ones EX moving towards you while spam jumping/punching
Interactions
-Changing the npc hp
-toggle if it regens or not
-making it knockback immune
-making it damage immune
-changing its properties, such as an effect like stoned, stardusted, or enlarged, and how long it does that
Others
-option to see hitboxes (also in aw)
-an option to see the damage done in an interaction (ex. pirate anchor) and the total damage done to the npc
-an option to see a stopwatch that starts when a npc takes damage and when it dies, and a toggleable normal stopwatch.
Buttons to
-stop/start an npc ai
-execute NPC
-Reset the NPC to its spawn location and health
Multiple NPCs can exist at once with different properties. (EX: a knockback immune, then spawn it, then change settings so it does take knockback, then spawn it)
It should also be easy to change abilities once in the dimension, too, so you can do side by side comparisons to things such as damage/knockback