Team Project does not want to open

Can you post those troubleshooting tips for others?

That's a shame. You mentioned you did a clean install, is it possible that the drive the media was on change letters? Not sure if that would have an impact. 

Here's an old thread with some suggestions from one of the Premiere Team members. These might work, but they might also result in some less-than-desireable outcomes: https://community.adobe.com/t5/team-projects-discussions/team-projects-stuck-on-quot-processing-loaded-assets-quot/m-p/9819907

How long is it getting stuck at this point? Thinking back to an old Team Project that I worked on, when I loaded the project on a new computer after it had become pretty massive, it took a long time to load the first time (and consequently populate the two folders I had you delete). Is it possible you need to wait a long time? I'm guessing you have, but you also said "tons and tons" of media. Team Projects have gotten some pretty significant performance enhancements in recent years, so I would hope the same issue I had isn't a problem now, but I can't be certain. 

Do you have another machine you can try to load the project on? You don't need the media to try, it can be any machine you're logged into and everything should be offline. It could be a good test to see if you can load the project at all or if there's perhaps a bigger issue going on.