27.5" being slightly smaller is easier on the drive train. If going mid-drive that may have factored all that in.

But, since you will not really be using it as a true MTB, why not look at options?

I'm converting a Specialized Hardrock Sport (hardtail) into an e-Bike. I junked the useless heavy front fork for a nice used Manitou R7 that took more than 2 lbs off the bike and is much more supple and responsive. I'll install a Thud-Buster suspension seatpost to help with the hits to the rear end. And I'm running a Schwalbe Fat Frank in the rear. At 40 psi it'll absorb quite a bit before it even gets to the seatpost

Point being, you can kit build a commuter around a nice sturdy MTB frame (this one is aluminum). With the battery out, it's prolly liftable to a roof rack. Certainly it'll go onto a bike carrier on the back (hitch mount). And the ride is very decent on rough'ish roads.

I'm using a TSZD2 mid-drive that has built-in torque sensing crank spindle so it's pretty intuitive and natural. No throttle, so pretty much Class 1

Kits are here: TSZD2 Kits