For your specific needs, a straightforward 125/160cc commuter bike would be the best fit. If mileage is the absolute top priority, then going for something in the 125cc space like the Honda Shine, Hero Super Splendor / Glamour models will be advisable.
If you want something a little more powerful, then bikes like the Honda Unicorn / SP 160, Bajaj Pulsar N160 and TVS Apache RTR 160 4V single-seat variants are machines you should look at.
The Avenger will be able to do what you are looking for. But being a cruiser, its ergonomics are very laidback, and its suspension isn’t the most comfortable either.
We would recommend taking a two-up test ride of each bike you consider before you make up your mind.