I wouldn’t feel comfortable with committing to a car for 3 years without a few hours unaccompanied test drive and certainly not having to go around a predetermined route, as that will have been planned to show the car in its best light, avoiding types of roads that it may not be so good on.
I’ve had two test drives in a BMW this week from different dealerships. The first was 2 hours and the second was 4 hours. Unaccompanied, no restrictions and no need to refuel. I was able to test the cars on motorways (tarmac and concrete sections), A roads, country roads, around town, in traffic etc. All critical to know if a car is right for you.
I’m test driving a Volvo this week and they tried to say that test drives were 30-45 mins. I said that was not long enough so we agreed on 75 minutes. Still too short really but probably long enough to know whether it’s a contender or not for me. My advice would be to push back and insist on a decent unaccompanied test drive. If they won’t agree I would try another dealership.