Yeah, I feel like Nintendo would have to.
The ability to output in 4K would be a generational leap in hardware power, significantly greater than even New 3DS was for example which was a lot more substantial than I think a lot of people realize (i.e. double the system RAM, 66% increase in VRAM, one of the CPUs was nearly four times faster while the GPU and other CPU remained the same).
From what I've read, even on low estimates, the new Switch could reasonably be a successor based on hardware specs. DLSS requires Tensor Cores which the Tegra X1 and Mariko do not have. However, Nintendo marches to the beat of its own drummer. I think it considers functionality to be what separates generations rather than hardware specs. The problem with that is no one else thinks that way so Nintendo may be complicating something that isn't complicated which to be fair, is on brand for the company. We're looking at something that could be Switch 2 that Nintendo potentially markets as Switch Pro (that won't be the name), then an alarming amount of developers don't really make use of the additional processing power and more modern techniques that would be available. DLSS isn't something you turn on by pressing a button; you actually have to implement it.
Personally, I buy most new Nintendo hardware (I upgraded to both DSi and New 3DS XL). As a consumer, it makes no difference to me what Nintendo considers this new Switch though I admit I'm an outlier. Trying to view this from a business perspective, I don't see any benefit to selling a new Switch as a mid-generation upgrade. If Nintendo is going to go through the trouble of paying Nvidia for a SOC capable of outputting in 4K, it should want every developer to make the most of it. That's not really going to happen if it's viewed as an optional upgrade instead of the main platform moving forward.
That said, who's to say what Nintendo actually does? Probably a mere upgrade though I'm on Team (Should Be) Next Generation. There's no reason to stop supporting Switch as long as the new one is backwards compatible in part to aid in the transition. Nintendo didn't stop making 3DS until last year. Similarly, Kaz Hirai predicted PS3 would have a 10 year life cycle. Sony didn't end production until 2017 so technically 11 years.