I am having a similar issue, on a Mac Pro 2019, 32gbRam, Radeon Pro Vega 20. The launcher freezes on the preparing page. I’ve never had this problem and have been able to install and work the launcher on laptops with way less power.
Its the first time i’m opening the launcher after download on this computer, so there should be no projects or games interfering.
I’ve tried just about everything on all the forums and nothing works.
I am extremely frustrated as I have lots of work to do but launcher wont work.
I emailed support got one reply and nothing since, its been almost a day.