I'm sure you've thought of this, but maybe just get a motorcycle? They're not that much harder to ride than a Vespa, and while they're a bit more dangerous, most of the danger either way is getting hit by a car...

A lot of what made Vespa-type scooters historically pretty cheap was the 2-stroke motors, which are being phased out because they're unreliable and bad for the environment. But, they were cheap. Unfortunately, as you've discovered, the 4-stroke scooters are now much more expensive. And for whatever reason we're not importing a lot of electric scooters (tho where I live people love renting those Lime scooters, but you can't like, buy an equivalent vehicle).

Random thought that may not be helpful: When I lived in NYC there were lots of delivery guys with electric scooters. Maybe try to find out where they're getting them?