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. 

Between the Honda H'ness CB350 and the Triumph Scrambler 400 X, we would steer you toward the Triumph bike purely because it offers you significantly higher performance for not that much more money. The Scrambler is also a smooth, comfortable do-it-all motorcycle which has good passenger accommodations as well. The H'ness is also comfortable for two-up riding and is a good city bike, but it will not be able to match the Triumph's performance advantage. 

We would advise you not to go for the Royal Enfield Super Meteor 650 because it is a rather heavy bike at 240kg, which will not be the best fit on traffic-riddled city roads. Moreover, its stiff rear suspension will be the bigger reason to look elsewhere. If you want a RE 650, we would recommend taking a look at the Royal Enfield Interceptor, as that has more pliant suspension and is also much lighter. 

Bajaj has decided to downsize the 400cc Triumph and KTM models in India to ensure these bikes attract a lower 18 percent GST in comparison to the 40 percent tax attracted by machines over 350cc in accordance with the government's GST 2.0 regulation. 

The Speed 350 should be very similar in terms of its mechanics to the 400 - save for the smaller engine and slightly lower performance - and will most likely have a more competitive price as well. 

If you don't want to miss out on having a 40hp, 400cc bike, then you should buy the Speed 400 before it is replaced by a slightly smaller machine.  

Of the three bikes you're considering, the KTM 250 Duke will be the most engaging handler, but it has the least peak output and the smallest engine. This means you will have to rev it more to access the meat of the performance.

The Triumph Speed 400 is the most powerful bike of your shortlisted options. It will be a great city bike because of its effortless performance and plush suspension.

The TVS Apache RTX 300 is sure to be the most comfortable machine of the three. Its long-travel suspension and commanding ergonomics help, but it is also the tallest and heaviest bike on your list.

Take a test ride of all three to see which one fits your needs the best.

Since you have mentioned you want a powerful motorcycle, we would recommend you look at the Triumph Scrambler 400X, KTM 250 Adventure and TVS Apache RTX 300 in the ADV / Scrambler category. Of the three, the Triumph bike is the most powerful, but it is also pleasantly usable inside the city, whereas the KTM and TVS are more do-it-all machines that will also be wonderful on a day-to-day basis. 

Coming to the Xpulse 421, there's no official communication from Hero on when it will be launched, so we would recommend going with any of the other options you are considering. 

Take a test ride of whichever option you shortlist before you choose. 

Both the Bajaj Dominar 400 and Triumph Scrambler 400 X are reasonably reliable and hassle-free machines, and considering they are both made by Bajaj, they should be light on the wallet in terms of maintenance. We recommend choosing the one you are more comfortable with and the one that has a service centre close to you. 

Coming to why we haven't reviewed the 2025 Dominar 400, that's because the bike is mechanically the same as when we reviewed it last in 2021, and the only tangible difference is the new LCD borrowed from the Pulsar NS400Z.