I have a Specialized e-Road bike. I am a solo rider. If I want to work hard I set the assist at the lowest level. My thought is I am setting low enough that I am just overcoming the extra weight of the bike. Trying to make it feel like a non-assisted bike. If I want to go fast I bump up the assist. Typical ride is about 20 miles I go out 15 at the lowest setting then I crank it up to Turbo for the last 5 miles home. You still work but not quite as hard but you can go 25 MPH fairly easily. It's a very fun bike. I still ride my Domane as well if I want a true road bike session.
I am still trying to figure out the optimal way to train with it but its been fun.