Sorry to hear about this! I’ve looked at your output_log and it indicates an additional crash log was created at C:/Users/ECCLES~1/AppData/Local/Temp/Eleventh Hour Games/Last Epoch/Crashes. Please upload the one that matches the time of the output_log you just posted (multiple crash reports are kept).
If you haven’t already, I would recommend following this support article. I haven’t heard of the game failing to be recognized by steam outright, so I can’t give more specific advice unfortunately.
If the problem persists after verifying the game’s files (or re-installing if necessary), it would be helpful to get more log files from you. This crash you uploaded occurred when entering Council Chambers, but if you crash when entering a different zone or even during normal gameplay, it’s worthwhile to upload the output_log and crash log again.
Thanks for taking the time to post and get us log files, I appreciate it!