Well,
you can just use your enemy, once get killed , you leave it exist, you can delete the mesh or just hide it … and keep it so you can add a delay to check , every 10 seconds if the player location - the spawn location is < of 300.
Then you have to break the loop.
If you have a “enemy spawner” you can do it inside that.
Once the enemy is killed , he send a custom event to the spawner ,
he will check every 10 seconds if the player location - the spawn location is < of 300.
Then you have to break the loop.
To break the loop you can use a loop connected with a gate node to that can turn off himself
here the page with the flowwwss