The Nintendo Switch model number HAC-001(-01) with serial numbers that begin with XKW will feature improved battery life that ups what you normally get from 2 to 5.6 hours to 4 to 5.9 hours, which is better than what the Switch Lite is getting.
Previously, Nintendo filed something called a "Class II Permission Change" to the FCC, which found the company asking for permission to change one of its existing products. This ended up being a souped-up version of the Switch and different than previously thought, and it looks like Nintendo has formally announced its refreshed Switch by way of adding a new model to its library of consoles.
In addition to the new Switch model, Nintendo is bringing out two sets of new Joy-Con colors, with blue and yellow as an option and purple and orange as another. Of course, these new Joy-Con controllers are not going to be compatible with the Switch Lite, so you'll have to get a regular Switch or one of the refreshed models if you want to jump on that. And unfortunately, you still can't buy two of the same color (or one of the opposite side) for some bizarre reason. Nintendo doesn't make a lot of sense in that department and probably never will.
If you've yet to buy a Nintendo Switch, it might be a good idea to go ahead and figure out which version is right for you ahead of the Nintendo Switch Lite's release this September. And if Nintendo is working on an even more powerful version of the Switch eventually, that's definitely going to muddle things.