I had 6 beholder fights in my campaigns and loved them all.

I found the interesting puzzle was almost always connected to terrain/minions :
The beholder cannot use their beams in their own anti magic cone. If the lack of terrain/minion makes it trivial to get in and out of said cone, the fight will be swingy but not really interesting.

Of course like every fight against a smart opponent, HOW they engage changes the game. A round of surprise amps the tension tremendously, for example.