KTM uses the batteries with larger capacity since the 2018 models came out.
We had them both, the old battery lasts around one hour on mild enduro tours, the new ones 1,5 hours.
you can use the old batteries in the new bikes and also the new batteries in old bikes.
Changing the batteries is possible within around 30 seconds max.
we always had one battery in the charger and one in the bike, so we could ride the whole day without having to wait for the bikes to charge. Here in Europe you find good used bikes older than 2018 starting from 5500 eur, newer ones start from 9000 eur. Old batteries are available from around 1000 eur, brand new ones cost nearly 3000 eur. So if you have a power outlet near your track as we have, it makes more sense to buy an older bile and two battery packs. Also the new bikes do not have more power than the old ones, they only have a slight suspension upgrade, wider handlebar and regen power but only in map 1 which you will never use.
the only thing that broke during the last few years on our three bikes was a water pump, so it turned out that they are really reliable and make much fun in the woods.
of course they are absolutely not comparable with the Alta, many components were taken from the KTM sx 85 and it is a huge difference in size and power to the Alta.
i would recommend the KTM mainly to use in the woods. ideal bike for beginners, teenagers or smaller persons, as long as you do not take it to a large motocross track with huge jumps and long straights you will have tons of fun with it.