GREAT DEPTHS WORM DOES NOT SPAWN

I'm in my 345 days world, with both rifts open, and the boss never appears.

Because of that, I've changed the world settings to great depths worms ALWAYS APPEARS and still all that I get is the regular waves of depth worms...
I tried to rollback at the wave's days to increase my luck, but without success.

Gosh, I wish that someday we'll get a way to invoke the boss without RNG.