Hey :)

In your case, I'd advise to start by checking the integrity of the game files through Steam, to make sure everything is in order!

Also, if you haven't already - I've noticed restarting Steam tends to resolve the issues wrongly warning about Steam not being connected.

Hope this help, don't hesitate to post again if the issue persists!

I appreciate your reply but I did mention verifying cache and restarting the whole computer (steam obviously included)  didn't help.

I had the same problem https://www.games2gether.com/endless-space-2/forums/114-bug-reports/threads/26899-pc-game-freezes-intermittently-on-startup-loading-screen-when-video-introduction-skipped

after updating to the patch. Waiting through the introduction cut-scene made it work for me. Skipping would make it freeze in the same place (sometimes). 

Anyway, your diagnostics file looks pretty much identical to mine "Object reference not set to an instance of an object" and *stall*. 

My naive guess is a race condition. 

Mh, glad you guys found a workaround - I'm going to check with the relevant members of the team to ensure we're keeping an eye on this weird issue!