Hmm. 30 mph cruise bike easy peasy. 35, and assuming you mean to pedal at that speed, amazingly harder to pull off.
This is where I start saying get a small motorcycle, to a lot of first posters, those that are older, fatter, etc.
But you are an avid cyclist, likely still able to break or wear out chains. You need a fast e bike because you like riding pretty fast now. So it starts there with your bike selection. You need a fatter tire for that gravel part, so likely an mtb with a beach cruiser tire on it. 26 inch wheels. But most mtb's cant mount a 52 tooth front crank from a road bike. Sourcing a huge front ring that actually can mount on an mtb crank is also not so easy. But your starting point must be to look at the bike, and see how much clearance there is at the rear chain stay for a much larger front chainring. Once you find that, then your bike is doable, including pedaling along at 35 mph. But that one item is really your problem, even for pedaling along at 30 mph. Stuff like bars, and seats, etc are yours to choose to your liking. Me,, I like to sit up more and see that car trying to kill me on a commute. As a real cyclist, you know how important bike fit is, and make it fit you.
Now to the motor stuff. All you need is a relatively cheap direct drive 1000w motor kit, and 52v nominal voltage battery. 750 wh is enough, and the stock kits will cruise at 30 mph leaving the house, and 25 mph or so towards the end of the ride.
That's not your 35 mph, but you can get there later if you still want it. I still suggest limit out at 30 mph, using 52v stuff for now. Later on, you can upgrade the battery, the charger, and the controller to hit faster speeds. But many affordable, but not cheap ass mtb's are not so stable above 30 mph on pavement, so I suggest you try a year at 30 mph, before you opt for more speed. and then maybe,,, opt for a motorcycle after all.
I don't commute anymore, but I still ride my e bikes.. I love my ebikes, even after one burned my house down. But when I go 40 mph+ I do it on a very very affordable 85 mph capable scooter. I just find the e bikes really shine at 25 mph or less. To go faster the bike lane does not cut it anymore. So full of sharp garbage you can't see going 35 mph. So I get in the lane, and do the speed limit on the scooter. At my house, that's 45 mph or more to keep up with the cagers.
But what I just said is not the only way. When I choose to, I can hit 40 mph on a modified beach cruiser. ( put a 72v controller on it) It does start to speed wobble at about 35 mph, but at these speeds its a moped, you stop pedaling this bike at about 25 mph. Oddly enough, a vintage 52 tooth front ring from a Schwinn vastity bolts right on a modern Schwinn beach cruiser. Mostly, I ride this bike to a grocery, 5 miles away, and 25 mph and still pedaling is the mode. I lengthened the bike, and added 7 rear gears and disk brakes. Longtails make great commuters, because they can carry the grub home, and carry bigger batteries. They don't need suspension because of the location of the seat is away from the rear wheel.