Some encounters should be fled. If you have a campaign that doesn't have an encounter that will kill the players unless they run, I think you have removed the danger of death which is part of the fun of playing. Every player character should be one encounter away from potential death. Not having encounters that overwhelm the PCS robs them of the joy of coming back 5 levels later and trashing that SOB 🤣. In your example, I would have the beholder at full power full hit points and full abilities. I would however telegraph its presence so that the player character can choose to avoid it if they are paying attention and role-playing.
@crappphone7744 If playing regular dnd then yes absolutely to what you mention. In my game however things happen a bit different. 🙃 but ya players learn to recognize that they prob shouldnt pursue combat every encounter if they want their pc to continue to live
