My opinion is that they weren’t explicitly trying to entrap anyone. The Russian collusion is a convenient excuse for putting the campaign under surveillance just so they could keep tabs and respond accordingly. It was about winning.
It was much more than that. Not only was the campaign being monitored, but also, the Trump transition team and his Presidency were being monitored to overturn an election. Rosenstein signed off on the last renewal of the FISA warrant. The Dems and the swamp wanted to destroy Trump.