Great chart! But it's so weird to see companies go on a hiring spree AFTER their product was essentially done. I cannot name a single feature that I use that wasn't present in the 2020 version. Since then, their headcount has more than quadrupled. What are those people doing?
Unity is currently redesigning their engine from the ground up using an ECS architecture. They're calling it DOTS or Entities.
Unity merged with a bizarrely-managed malware company a while back and shouldn't be used as a measure of anything.