Worked for a mobile game company in 2020 and 2021. Can confirm that 2020 was a very good year revenue wise, if not dying off a little bit towards the end of 2021
That makes no sense. 18 months ago was January 2021. For Unity to be down now compared to then is fully compatible with the idea that (1) 2020 and 2021 were high points for the industry, and (2) things have started to die off since the end of 2021. That's exactly what you'd expect.
But the fact that 2020 and 2021 were historic boom years means that the description of Unity as just lacking the war chest to weather a couple of bad years is nonsense. These were great years, not bad years.