Ok. In that case we would need the logfile to find out more. Either post it here, or on pastebin and link to it. Then I can compare it with my logfile.
Also, when you eventually try out the native version again, make sure to verify your sources after downloading (in steam). Cases where the download was missing stuff are not uncommon. If you ever used mods also make sure you delete them manually before downloading, and the proton-version stores them at a different place (which would explain that it works with proton, if mods were the culprit).