The first time I started it, it opened in a very weird resolution (3388x2222) which, to me, is a known bug caused by Unreal 4 not handling DPI awareness correctly (my desktop resolution is 3840x2160 @ 150% scaling). In TSW3, the workaround is to set the compatibility options for the executable to perform DPI scaling by application, and then it works. When I try this in TSW4, I just get a black screen after the first splash screen, and nothing further.
Managed to get it to start correctly by overwriting the default user TSW4 config files with the ones from TSW3. This feels pretty janky, but it worked.