I know it's quite an edge for premium users, but please... The community has been suggesting this one for a very long time already. We will buy Unity if our games will make it big. For now, almost all game engines out there has a dark mode feature even in free versions of their engines. I have been using Unity ever since I started out game development last 2013. People have been complaining about eye-strain, specially when you're working late at night.
Please listen to your user base. Thank you in advance!