Singleplayer doesn't start

[RufGTI]

Running the launcher and selecting single player I see the rF2 logo appear and then nothing happens. The launcher itself seems to work, I'm also able to run the dev demo (no idea whether that's helpful). I don't use any VR hardware and didn't install any third party plugins, OS is Windows 10 64 bit. I already did the Steam integrity test and ran the .exe with administrator rights.

EDIT: Started it with trace=100 as command line. This is what I got:

TRACE LEVEL = 100
   0.01s tracelog.cpp  218: Command line: "+path=".."  trace=100"
   0.01s main.cpp      358: Version=1.1108 Build=1108
   0.01s main.cpp      359: FPU=0x0008001f
   0.01s game.cpp     1421: Setting Mod Path "Packages" 1 0
   0.25s game.cpp     1817: Entered Game::Enter()
   0.25s osman.cpp     901: Entered OSMan::Enter()
   0.28s osman.cpp     963: exe is 64-bit
   0.28s hwinput.cpp  7898: Entered HWInput::Enter()
   0.28s hwinput.cpp  7899: HKL=0x04070407
   0.28s plrfile.cpp  2934: Entered PlayerFile::Enter()
   0.35s hwinput.cpp  7966: DirectInput enumerated 0 game controller(s)
   0.35s plrfile.cpp  2102: Attempting to save to D:\SteamLibrary\steamapps\common\rFactor 2\UserData\player\player.TMP
   0.37s plrfile.cpp  2126: Retcode: 0 for renaming to D:\SteamLibrary\steamapps\common\rFactor 2\UserData\player\player.JSON
   0.42s plrfile.cpp  1762: Could not find PLR file and failed to create one!
   0.42s game.cpp     2604: Entered Game::Exit()
   0.42s sound.cpp    1675: Entered Sound::Exit()
   0.42s specialfx.cp 4543: Entered SpecialFX::Exit()
   0.42s hwinput.cpp  8197: Entered HWInput::Exit()
   0.42s dynman.cpp   3051: Entered DynMan::Exit()
   0.42s render.cpp   3068: Entered Render::Exit()
   0.42s onscreen.cpp 4224: Entered OnScreen::Exit()
   0.42s vidman.cpp   3083: Entered VidMan::Exit()
   0.42s osman.cpp     971: Entered OSMan::Exit()

What is a PLR file?