Got 2 monitors, one 4k, the other 1920-1080. RTX 2080ti, both display-port connected. Windows LTSC fully updated as are the NVIDIA drivers. Starting TSW2 switches off my 4k main monitor. Switching the 4k off & on, and then all is OK. except that my second monitor seems un-sharp. TSW2020 and Train Simulator 2021 have no problems .... Other games also behave OK. I guess TSW2 has a windows scaling problem.
got 2 x4k 58'' screens and the same happens to me. it's the only game i cannot use in dual screen mode.