Among the RE 350s, you can consider the Hunter / Bullet / Classic models for their comfortable ride, neutral ergonomics and smooth as well as characterful engine. In a similar vein, the Honda CB350s also warrant strong consideration for similar reasons. 

All the Harley-Davidson X440 models have a similar riding experience and only differ in terms of features and design, so pick the one you like the most. 

Lastly, we would also recommend you take a look at the Triumph Speed T4 and Triumph Speed 400 as they offer great performance and quality at a reasonable price. 

Take a test ride of all the bikes you shortlist before you decide. 

Taking your considerations into account, bikes we would recommend taking a look at are the Triumph Speed 400 and Scrambler 400 X / XC. 

Both will offer you considerably higher performance than your Yezdi bike and will also be comfortable enough to handle daily commuting duties while being brisk enough on the highway as well. 

If you want an air-cooled, torquey engine, then you could even take a look at the Harley-Davidson X440, which is a comfortable neo-retro roadster that has decent performance. 

Take a test ride of the machines you shortlist before picking one.