Is it too simplistic to think that Trump comes out of this weakened and Pelosi emboldened?
Well, there's always a long game at play right?
Trump's people knew that he was pissing everyone off with the shutdown, and not getting any closer to an outcome he liked. He couldn't get his wall funding when his own party controlled both chambers of Congress and he certainly wasn't going to get his wall funding
after losing a landslide election, and I suspect he figured that out pretty quickly if he didn't already know it going into the shutdown in the first place. So what's the play here? Why fold now?
I think he's hoping to transfer blame to the new bipartisan commission. He can just go to the republicans and say "you absolutely must get me my $5.7b for a border wall, and I won't sign any other deal" and that will effectively ensure the commission can't come to any agreement. Otherwise, the bipartisan commission from Congress is just going to come up with something very like the bipartisan compromise those same people came up with back in December, which initially said he would sign and then threatened to veto.
So after he transfers blame to the bipartisan commission, and then ensures that the commission will fail, Trump can say "Look I tried to make Congress do it's job and they failed to keep government open, so now it has to shut down again." That will give him the chance to blame Congress for shutdown round 2.
Either way he's not getting his $12b or even his $5b for a wall, so there has to be some other end game in mind. Maybe he's hoping to make Pelosi and the democrats look bad if they can't get recreate the deal from the last month. Maybe he's hoping to whip up some base support ahead of the next election, or at least convince democratic voters that congressional democrats are sort of equally corrupt and they should stay home on election day. Ultimately, I suspect that Trump cares about the actual wall a whole lot less than he cares about winning reelection in 2020 so that he can die in office and never face prosecution. If that's the case, then everything else is just prologue for the upcoming election.