I'm late to the party on this thread but will opine nonetheless. I'd definitely take the safer route at the cost of a few extra miles. the e-bike makes that amount of extra mileage negligible/immaterial. the safer route is the way to go (based on the info given by the OP). although perhaps there are times (like days preceding a holiday) where light traffic might make the city street route a reasonable choice.
I have a similar decision although it is only 4 miles of my total commute (36 mile roundtrip). Leaving downtown at the end of a workday, I can take a greenway to get out of downtown or use sidewalks and city streets to make it to a bike lane route. the greenway adds an extra two miles but getting out of our downtown area is probably the most challenging part of my commute. the bike lanes are okay except when there is a sporting event or concert. the bike lanes pass a large arena that is the venue for pro hockey, basketball and many concerts. on nights of an event, the bike lanes are particularly dangerous. lots of traffic comprised of many drivers who are in the downtown area for the first time. they are mostly focused on finding parking and are not focused on pedestrians or bikes. also, crowds of people headed to the venue will walk in the bike lanes. parking lot attendants will set out their signs and stand in the bike lanes with their flags. so I monitor the event schedule and on days of an event I always take the greenway. other days I usually head to the bike lanes and opt for the shorter, more direct route.
the greenway offers its own frustrations although it is certainly safer for me as long as I ride responsibly. in addition to the extra mileage it is slower going. for one, having an e-bike I don't want to attract attention so I keep speeds low. but for two, pedestrians insist on walking in the bike lanes even though there are marked and dedicated walking/jogging lanes. dog walkers also walk in the bike lanes. dogs on long leashes or not on leashes are frequent. the dogs will criss-cross the bike lanes and are as predictable as squirrels. most pedestrians will walk with their backs to the bicycle traffic and will not hear an approaching bicycle. so in addition to the extra mileage it is usually a slower go vs the bike lanes on the downtown streets.