Is the Demigod and simulacrum on the field of battle now or still in their hidey hole?Distant Empowered Freezing Sphere hits at 660ft x 2 (The Sorcerer and Simulacrum) + Celestials hits at 600ft.
It's instant death.
Outside of that, freezing sphere does what 10d6, so 35 average damage on a failed save*2, we get 70 (empowered let's you reroll some of those dice, so we could call it maybe 90), and a max of 120 on 2 failed saves, against a 20th level d10 hit die character (call it 124 hp before con mod, race or feats). Death here is very unlikely.
Of course this is also assuming you choose the right point to target against a target that can hide at +17 and/or be anywhere between 0 (takeout movement), 70-90 (bonus action dash and movement) or 500 (tree stride) from the point of attack (could hide and do this last one).
Of course this also assumes 2 failed saves against 0 damage mitigation. And the Ranger has several options there as well depending on subclass.
And I'm ignoring the Avengers, they will either never be close enough, as the Ranger bonus action dashes, or they won't have a target (with their mighty +2 to perception), or they'll be dead from getting attacked with no ability to counterattack for awhile.
So, what happens after you and your simulacrum's blow a spell slot and 2 sorcery points to certainly fail to kill the ranger (and potentially to fail to even do any damage at all)?