For legend plus the hp is lower so Wee Jas needs about 20.6 million damage to kill. I can hyper 1 Dios but I'd rather not hyper 3 if I don't have to.
If you can, try running endless coop. depending on your Dios levels (mine aren't max level yet) you can see how much damage you do. You'll be around level 32 based on the videos I've seen. You need to average 3.44 million per sub to kill Wee Jas, and if you can then Myr is toast. I also think you need a buffer over 26k HP to eat the first couple hits from Myr's final form which in coop should be trivial.