So it looks like a misread/misheard Barr's letter on obstruction of justice. I thought it said Mueller couldn't decide,, so he referred the matter for the AG to decide. But reading the letter directly, it was Barr who took it upon himself to make the decision on obstruction of justice, Mueller did not request this. It seems like Mueller provided arguments "for" and "against" and was going to leave it up to Congress/Public to decide, not the AG. So this really was the Barr Report, not a summary of Mueller's findings.
I'm so gaslit I'm starting to wonder if maybe the whole thing was just the Trump family being dumb and surrounded by criminals.
This is my theory on what happened.
Early/Mid 2015 - Trump ran for President purely as a marketing gimmick and branding exercise.
Late 2015 - After surging surprisingly in the polls after the GOP debates, Trump decides to leverage his popularity and potential influence by trying to setup a Trump Tower Moscow deal that's he's wanted for decades. This was still before the Iowa Caucuses so I'm guessing things still didn't seem real to him because he still hadn't won a single vote yet.
Early 2016 - Trump starts to win some primaries, but still doesn't think he'll become the nominee, so he pushes ahead on the Trump Moscow deal. Russia previously was just interested in causing chaos in the 2016 election, now begin sending out feelers to the Trump campaign to see how much they can influence Trump and his associates. Also around this time Trump starts to hire campaign staff that are unusually friendly to Russia or have extensive Russian ties. It's still unknown how Trump found these people but again due to the pending Trump Moscow deal, he might have been open to hiring people with good Russian/Putin connections.
Mid 2016 - Word is beginning to get out that Russia has been hacking into various US political operations (ie. DNC). Trump realizes he needs to keep the Trump Moscow deal under wraps and put it on ice. In the meantime, Russia tried again to insert tentacles into the Trump campaign (ie. Trump Tower meeting). At this point, the Trump campaign was clearly interested in dirt on Hilary no matter the source. Not necessarily to win, but to at least bloody her up. On a separate thread, Manafort is now running the campaign and is using his position to pay off his debt to Russian oligarchs. This is probably the closest they came to collusion, but not enough to meet a legal standard of conspiracy between the Trump campaign and the Russian government.
Fall 2016 - Roger Stone was probably in communication with Wikileaks on some level and he likely gave Trump the heads up about this information (I bet this is in the Mueller Report). But again, it's not clear if Roger Stone knew he was getting information from Russia and even if he did, it's not clear if there was a quid-pro quo. By late fall, Russia was clearly pushing Trump hard and Trump was amplifying their message perhaps unwittingly via Wikileaks or other sources. But he knows Russia is now sensitive issue, it's coming up in the media and in debates. He knows he's vulnerable because of the Trump Moscow deal. If the public found out about that deal, then everyone would think Russian collusion is real, so this is the genesis of all the lies about Russian contacts.
Early 2017 - The intelligence agencies declare with high confidence Russia interfered with the 2016 US election. Trump continues to deny this for many months into his presidency. The reason is two-fold, Trump still probably wanted to make the Trump Moscow deal happen down the line, but more importantly Trump is subject to blackmail by Putin due to the Don Jr. Trump Tower meeting, which the public didn't know about yet and the Trump Moscow deal. Those two things, Putin could expose Trump at any moment. This is the real reason Trump was so careful not to upset Putin.
Various Putin Meetings / Helsinki - By this point, the Don Jr. Trump Tower meeting had been exposed, but the public was still clueless about the details of the Trump Moscow deal. Also was and still is clueless about the various backchannels that Kush tried to establish with Russia and whatever Manafort was up to. I believe the meetings where Trump tore up the notes is where Trump and Putin tried to tie up those loose ends or Trump simply was ball-washing Putin's nutsack because the existence of those loose ends even if they weren't discussed.
Long story short. Trump probably was too incompetent to fully coordinate with the Russian government in regards to hacking/election interference and relief of sanctions. But Trump's outreach to Putin in the middle of the campaign about a Trump Tower Moscow deal and then later the Don Jr. Trump Tower meeting, essentially turned Trump into an unwilling Russian asset and made him compromised. This doesn't rise to a criminal conspiracy, just like how Carter Page was never charged. Donald Trump is basically an older and more orange version of Carter Page. Mueller's Report will probably detail Trump's incompetence / negligence even if there's no behavior that meets a criminal standard of collusion.
One thing I still can't explain is why Trump was so relentless in obstructing the investigation. It went beyond the annoyance and frustration of being investigated, he aggressively tried to smear everyone in the FBI leadership and everyone in the special council office. Trump acted like a very guilty man and I don't know if the Trump Moscow deal can explain all that behavior. I mean he was still freaking out just a week ago, so I'm struggling to square that circle.