Trump only cares about winning; he doesn't care how he gets there. Ryan has created this mess and the hurdle is going to be getting past Ryan and his cronies. The House is now very divided. From my understanding there was a plan back in 2015 that already passed both Houses but Bammy refused to sign it. Remember; Trump and Ryan (along with Preibus) made a deal a long time ago. With any luck, they'll show Ryan the door just like they did Boehner.
Ryan needs to be very worried about Ted Cruz.
Nobody ever said Ted Cruz had anything to do with removing John Boehner from his position as speaker but the way events played out it sure looks like he did.
On September 24 2015 John Boehner held a press conference to arrogantly state to the media that he would remain speaker and wasn't going anywhere.
That very evening Ted Cruz held a meeting with conservative house members.
On the morning of September 25th 2015 John Boehner held a tearful press conference to announce his resignation as speaker of the house and his impending retirement.
I don't know if Ted Cruz had anything to do with Boehner's resignation but it sure looks like he did. Unfortunately he had no influence over who replaced Boehner but if I recall he seemed to lean toward Mark Meadows.