Between the diesel Mahindra XUV 7XO and the electric XEV 9S, we think you would be better off with the XUV 7XO since your main purpose of the new car is to go on family trips. 

Highway charging infrastructure is still developing, and quite a few times, existing chargers are either occupied or not operational. 

Thus, if your trips are over 300 km long, you would need to stop and charge. This will ensure you can make it back or even have sufficient charge to drive around when you get to your destination.

Moreover, if these trips involve hill climbs, you will lose battery charge much faster. Conversely, the diesel Mahindra XUV7XO will be just right for these conditions. The torquey engine is powerful enough to tackle climbs, and with diesel being the fuel of choice, there will be no range anxiety.     

Mahindra XEV 9S Pack Two above 70 kWh, battery pack can be a good option for you. It is a spacious and practical EV, and if you don’t plan to use the third row, you benefit from a larger boot as well. 

Mahindra has spread the features well across the range, so even the lower variants feel adequately equipped. The car supports fast charging, which helps reduce charging time on highway runs. 

While the claimed range is 600km, the real-world range will be lower, but it should still be good for your kind of highway usage.

As a city car, the Mahindra XEV 9E/9S offers a good range and will work well. You’ll typically only need to charge it every couple of days, depending on your usage. In fact, if you have home charging, an EV is even more convenient than an ICE car. 

On the highways, it's a different story altogether. A road trip in an EV can be an adventure, as the public fast-charging network can be hit-or-miss. With some proper planning and back-ups (for charging) built into your itinerary, it is possible to travel across India except for very remote locations. 

The good thing is that the XEV 9E/9S has a good range, and you can comfortably get 400+ km on one charge with some careful driving. 
The software issues are largely resolved, as Mahindra is constantly updating the software on its EVs to iron out bugs. We have also seen a dramatic reduction in customer complaints. 
Though the XEV’s INGLO platform is designed to take AWD, the cost of an AWD variant is too high. Therefore, Mahindra doesn’t feel that there is an immediate market for it. Hence, an AWD variant is unlikely to be launched in the coming year. 

Given your requirements, the only options that are not wildly expensive are the Mahindra XEV 9S and the Kia Carens Clavis EV. Both are three-row SUVs that are pretty spacious and practical, but they differ in what they offer.
The Mahindra car comes across as the more premium of the two. It’s larger, has an imposing road presence and comes packed with technology and features. It wins the spec-sheet war and is a very comfortable, compelling option. However, once you consider how the car will be used, the Kia Carens EV could be the better everyday car.

One of the most significant factors is access to the cabin. The Carens Clavis EV sits lower, making getting in and out easier. Your requirement for a wheelchair suggests that someone with limited mobility will be using the car, and this is why the step-in height becomes something you notice every single day and a very important factor.

Also, the third row, too, is slightly more practical and usable in the Kia car. When the third row is folded down, the boot is spacious enough to accommodate a wheelchair. The lower floor also makes loading a wheelchair easier.

On the ownership side, Mahindra’s EVs have made rapid progress and the products are far more polished than before, but some owners still report software-related hiccups. Kia’s EVs, by comparison, are better sorted, suggesting a more predictable ownership experience.
Both cars are easy to drive; the XEV 9S offers a better ride and is more refined, but the Carens Clavis EV feels less cumbersome in tight spaces.
 

If you can install a home charger at your residence, then an EV is a good option for city driving. 

For just 1000km a month, you won’t really save much by way of running costs, but that’s not the only way to look at an EV. It’s a far smoother, nicer driving experience, and EVs make driving much easier. 

Yes, the Mahindra BE 6 has serious design flaws, and the lack of headroom at the rear is a big one. We would advise you to go for the Mahindra XEV 9S instead. If you can’t have home charging, then it's best to look at an ICE vehicle, in which case the Hyundai Creta 1.5 CVT auto is your safest choice.