[2020] For 6 months, we have had to either play with input delay or crash with exclusive fullscreen and everyone on mac or linux hasn't been able to play at all. There are 27 new stable versions on the Unity site. Can Facepunch please upgrade the broken Unity this month so exclusive can be default again?

All of those "27 new stable versions on the Unity site" are more broken than the one we are currently on. Yes, we've tried them all and reported every game breaking bug to Unity. The only good news is that there is a slight chance one of the next 2018.3 releases will allow us to upgrade.