Tier list ain't shit when it comes to outplaying your opponent.
She is probably 4-6 or 3-7 vs cast but just cuz a character has bad odds of winning doesn't mean the best player can't win with them.
Just like how sonic beat Forever King with Shao after he practicing for just 5 min.
The tools sonics uses to win is number of hit guess, mix (50/50), throw/staggers to open up opponents. The top tiers all have these tools plus a whole lot more. When we compare D'Vorah or Kotal to top tiers like Geras/Error/Sonya the difference is monumental.
D'Vorah has issues up close and no fast moves, Kotal is shit far away and close up do to frames and hitbox.
Even though its a bad matchup for Sonics it doesn't really matter since scar and rye will respect him in many situations instead of forcing the character in its weaknesses where it loses.
I don't think those players are putting D'Vorah where it hurts and that's why he is getting away with so much shit. Those bug setups go away on hit. At least I seen that on honeybees stream and that's why sonics is jumping right after setting it. He doesn't want normals to hit him. Projectiles won't be able to get them to go away.
She is also only getting 23℅ off combo so scar and rye made several mistakes in the neutral otherwise sonics wouldn't win.
Bottom line, D'Vorah, Shao Kahn and Kotal Kahn need buffs. They struggle in so many areas. Rye even said the only reason D'Vorah was winning was because it was Fox behind her.