The new Ride1Up Roadster V3 seems to be the best of the inexpensive light weight e-bikes. I can't vouch for it's quality as I've read mixed things about Ride1Up, but that would be my choice in this category.
I've enjoyed Ride1Up, but there are some issues around quality and longevity, which is common for many Chinese e-bikes in the price range. True longevity does seem to come with a higher price tag and more long-standing bike brands I haven't had a chance to ride the Roadster V3, but hopefully soon!
Yes, it's too stiff for gravel. It's disappointing because it looked like it could be a good fit! But I guess impact-resistant carbon fiber is too much to ask for at this price point