Since you are looking at hill climbing more than raw speed, and since all of the bikes you are looking at are mid-drives, you are most interested in the torque number of the motor. The Giant uses a Yamaha motor (maybe one of the most reliable) and has 80Nm of torque. The Specialized uses a Brose motor (probably the quietest) and has 80Nm of torque. The Trek uses a Bosch motor (also very reliable and maybe the most sophisticated) which has 75Nm of torque.
Probably wouldn't notice the mere 5Nm of torque difference unless the steepest climbs come towards the end of the ride.
Know also that the Trek Allant+ bikes with an "S" after the number are speed pedelecs which give assistance to 28mph. Allant+ 7 = assist up to 20mph. Allant+ 7S = assist up to 28mph.
I've got nothing against the Giant, but a modern bike of this caliber should come with a 500Wh battery at a minimum.
Some of the Specialized bikes did indeed have some significant issues. Bad that folks were without their bikes for a period of time. Good that Specialized seemed to deal properly with all of the cases I have read. I'm sure hoping that this has been addressed as I just took delivery of a Turbo Vado 4.0 a couple of weeks ago. Couldn't resist the sale Specialized was having, which resulted in that bike being $1065 off MSRP. But I believe that the sale ends tonight, so won't be any good for you. But maybe during the current recession Specialized will extend it?