First car – comfort at a reasonable price

Hello dear community, since I start working in the fall I want to buy my first car. Unfortunately I have no idea about cars at all and need your help! I will work in the field and mostly drive to the customer on Mondays and return Fridays, where the location can be anywhere in Germany. So I will be travelling a lot and sometimes also have to drive long distances. For this I need a car with appropriate comfort. At the same time I have as a job starter n The car should therefore cost around 500€, my upper limit is 700€. Also petrol consumption should not be too high. From the size I thought about a coupé or a 5-door, but of course any suggestions are welcome After 2-3 years I have the possibility on a company car, therefore leasen would be also an option. Probably my requirements are quite unrealistic – comfort and cheap price. I hope still, that you can help me a little bit. Thank you in advance!!! Marie