Once I deleted the (newly) DE shipped steam_api64.dll, game launched for me. Give that a try. They may have shipped a bad version?
mv game_data/Downloaded/Public/Tools/Windows/x64/steam_api64.dll{,.moved}
Was getting this error beforehand
0.069 Sys [Info]: Steam Service Initializing
0.070 Sys [Info]: Attempting to load steam DLL from Z:\mnt\games\wf\game_data\Downloaded\Public\Tools\Windows\x64\steam_api64.dll
0.071 Sys [Info]: Steam DLL loaded
Error loading steam_api64.dll (Proc missing)
0.072 Error [Info]: Assert: (Error loading steam_api64.dll (Proc missing))