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.
 

For city use, the Toyota Fortuner is not ideal. Since you have private parking that accommodates a charger, this is a perfect time to switch to an EV. The Mahindra XEV 9E is more appealing than the Harrier EV, but the Mahindra XEV 9S is the one to focus on because it is more practical and also costs less. 

It offers enough range for your 100 km weekend runs, has sufficient power and torque to tackle steep inclines, and has adequate ground clearance for rough roads. The Fortuner will handle rough roads better, but given that it is much more than the 9S. It is hard to justify the extra spend for occasional rough-road use.
 

If you don't need an additional row of seats, opt for the Mahindra XEV 9E instead of the Mahindra XEV 9S, for its driving manners. It is quick, the steering makes it surprisingly easy to drive, and its ride-handling balance truly feels world-class. There are some good discounts available on the XEV 9E, so you could get a good deal. 

The new Kia Seltos turbo-petrol is an excellent option too. However, no ICE vehicle can match the smoothness and seamlessness of an EV, and simply for that reason, the XEV 9E is the better option.
 

The Mahindra XEV 9S is a large car, but its last row isn't comfortable for adults over long drives. Hence, if you need a comfortable seven-seater for long drives, consider the Turbo petrol versions of the Kia Carens Clavis and Tata Safari instead. 

There's also the Kia Carens Clavis EV in this range, which shares its battery+motor with the Creta Electric. However, on your 350km+ highway drives, you will have to stop and charge once, as its real-world highway range is about 345km as per our tests