That Ubco is pretty interesting. Optimized more for off-road than for on-road, more an eMotorcycle than an eBike, yet weighs less than <150 lbs. Plus, most of that weight is low and centered, which makes for easy handling. Pricey, but most of this eTechnology is still pricey.
As for eBikes, the sweet spot price-wise is the hub-drive (motor on the rear wheel) eBikes, and I think stlrman has a good point. $1.5k will get you a good one. Not the same beast as the Ubco, though.
FWIW, I have a Trek eBike (Powerfly 5, a hardtail mountain bike that I use mostly on the road with semi-slick tires. It's about three years old, with the Bosch drivetrain that puts the motor at the crank (i.e. a mid-drive system), not at the wheels. The bike weighs about 50 lbs, but most of that extra weight is right around the crank, and that stabilizes the bike and makes it easier to ride--also produces the urge to go FAST! Still plenty of exercise if you want, because you can select the level of eBoost, and at the faster pace, your nervous system gets a very good workout! The current generation of my bike costs about $4k. Out of my price range now. If you were starting over, I'd go with hub-drive fat eBike from a non-big-name bike company.
(something like this:https://www.ebay.com/itm/750w-fat-tire-Thunder-Ebike-28mph/223551092627?hash=item340caef793:g:l0gAAOSwkItdAvSY
The Ubco is a major step up from that off-road-wise, and a bigger step up from that price-wise. (IMO, of course.)