What’s the maximum amount of lines from Sunbeam possible within a single round?

I noticed that sunbeam allows you to to create multiple lines within a single turn. What’s the maximum possible amount of sunbeam lines able to be created by a single caster within one turn?

For reference, the spell has a casting time of 1 action and states:

A beam of brilliant light flashes out from your hand in a 5-foot-wide, 60-foot-long line. Each creature in the line must make a Constitution saving throw. On a failed save, a creature takes 6d8 radiant damage and is blinded until your next turn. On a successful save, it takes half as much damage and isn’t blinded by this spell. Undead and oozes have disadvantage on this saving throw.

You can create a new line of radiance as your action on any turn until the spell ends.

Rules

  • Level 20 Character, any combination of multi-classing allowed
  • Only official material published by WOTC in book form is allowed. No Unearthed Arcana
  • Setup is allowed, including any magical items present in the Dungeon Master’s Guide or any other source-book. Items only present in campaign books are not allowed.
  • You may have 4 allies at level 20
  • Simulacrum is allowed