Respectfully, Zim, Trump knew a helluvalot prior to Jan 20, 2017.
He knew Comey was a slimey bastard who obstructed immediate prosecution of Hillary Clinton for the e-mail server, and that Comey had hidden and ignored the second cache of e-mails. No reasonable prosecutor MY ASS.
He knew that Hillary was actively starting the 'Russia is Trumps benefactor' by her accusations in the SECOND DEBATE of the 2016 presidential campaign.
He knew about the BUGGING of his 'meeting places, phone, and computer systems' immediately after the elections. That's the reason he LEFT those places immediately.
The 'orphans' meeting that was OBVIOUSLY a setup targeting his son, Donald Trump Jr, with a bogus meeting with a Russian Spy - placed there by Hillary and crew.
The timelines of 'when things happened and when Trump knew about them' do get 'obscured and obfuscated' the further we get from their origin.
There were a whole slew of blatantly obvious criminal actions that he saw well prior to taking office, including those of Øfurher Hussein.
His biggest mistake was in trusting his VP, Pence - who was up to his neck in sabotaging president-elect Trump and the Deep State minions that Pence was in bed with. The removal of FLYNN was entirely the doings of Pence.
Michael Flynn was well aware of 'things' and Pence IMMEDIATELY made moves to discredit Flynn and get him removed from Trump's presence.
There was more than enough to start criminal investigations into the 'evil empire' on Jan 21, 2017.
Pres. Trump's political advisors advised him against pursuing that very sane path. They were saying it would make him 'look bad' - and President Trump, unfortunately, heeded their advice.
Not so Today - He has learned his lesson, in spades.

Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good ...