If you continue to get a connection error when connecting through Steam, we recommend the additional troubleshooting steps found here that you've not tried yet.
sorry, already try it. Before posting it, i tried to search internet for clues , no success.
- no issue with other steam games, f.e. like Elite Dangerous
- i was able to run ESO via this .exe
"C:\Program Files (x86)\Steam\steamapps\common\Zenimax Online\Launcher\Bethesda.net_Launcher.exe"
Since you've already went through the troubleshooting here for the error "Login error: unable to initialize connection to steam" the next step is to open a ticket with customer support for further help.