This may be helpful: https://villanyautosok.hu/traveling-to-hungary-with-an-electric-car/
But if you're not used to an EV, this is not the time to try it out. Stick with a standard ICE.
Rather than renting a car for the entire trip, I would rent as needed. For example, there is no need for a vehicle in Budapest. Take a train from Vienna to Budapest, and if you want to explore other parts of Hungary, then you can consider a car rental.
Some important items to note:
1 . If everyone in your party is a wine drinker, you may want to explore tour options as Hungary has a 0.0% tolerance. Not even a sip is allowed.
2. You'll need a vignette for Austria, Slovenia, and Hungary.
3. Check your rental company to make sure you can drive from one country to another: https://www.autoeurope.ca/driving-information/austria/#:~:text=Rentals%20originating%20in%20Austria%20are,%2C%20Moldova%2C%20Montenegro%2C%20Poland%2C