Not sure why you would doubt the recommendation from a company with Yamahas' reputation. I tried the dense rubber pads first before getting the dielectric grease recommendation.
The rubber helped but I still had frequent shutdowns.
An engineer friend of mine explained that dielectric grease...
THIS^^^ worked for me . Applied dielectric grease to the connectors between the battery and motor and tightened the battery with a few pieces of dense rubber. I went from having shutdowns every other ride to none since applying the grease. Its been four months and I ride about three days a week...
Maybe not enough pressure? I run mine with 20 lbs back and 18 front on a 27.5 x 2.8 tire. The bike handles fine and I like the damping affect I think I feel. Im in a rocky area and they seem to smooth things out a bit.
I went with Tannus Armor inserts with tubes on both my bikes. Havent had a flat yet. Yes they add a little weight but I dont care, it doesnt matter much on an eBike.