Congrats and welcome aboard! Thanks for all that guidance up front. A few more things to have in mind as you shop:
Q1. How much can you spend beyond the $2000 voucher?
Q2. Any restrictions on the voucher we should know about?
Q3. Are you looking for easy pedaling or some work on typical rides?
Q4. What's your local terrain like? Flat? Gentle hills? Steep hills might favor a mid-drive over a hub-drive.
Q5. How upright do you want to sit? Too far forward can strain the neck and wrists on longer rides, but bolt upright can lead to butt pain.
Q6. Do you really need assist beyond 20 mph? If not, and you want a throttle, stick with a legal Class 2 ebike to stay on the right side of CA's latest ebike laws.
A good place to start: Go to your nearest ebike shops, give them all this info, see what they have to offer, and test a few different bikes if at all possible. That'll give you a basis for evaluating any suggestions you get here.
How much you'll enjoy a bike day to day depends a lot on how it feels to you in use. Testing for yourself is the only way to know that.
So, buy locally if all possible to (a) ride before you buy and (b) insure that you can get the bike serviced — especially the electrical part. Beware of no-name brands that might not survive the current market shake-up.
I'd recommend focusing at first on ebikes with torque-sensing assist. Cadence-sensing assist is generally less expensive, but power delivery will feel a lot less natural, and many find the starts too powerful.
If you'll be tackling big hills on a regular basis, test at least one mid-drive. But bear in mind that mid-drives are generally more expensive, require more drivetrain maintenance, and rarely have throttles.
A good reference point: If possible, try an Aventon Level.2 or Level.3 commuter hub-drive as a reference if nothing else:
o Good build quality, nice looks
o Reasonable weight and battery capacity
o Passable components
o Decent power, torque, and climbing performance for a 500W hub-drive
o Well-implemented torque-sensing assist and progressive throttle
o Fairly nimble
o Useful rear rack
o Large national dealer/service network (likely a market survivor)
o Under $2,000
I've ridden my neighbor's Level.2 enough to know that it's a good value. And it works fairly well in our hilly terrain. The Level.3 just came out, so look for Level.2 discounts.