For whatever reason people really want Nintendo to fuck everything up by releasing a "New Switch," but there's no indication that will be happening. There's no more miniaturized version of the TX1 in existence, and Nvidia's focus seems set on everything else except miniaturizing/advancing the Tegra line right now. At best we'll see minor changes to joycons or the kickstand or something. 2021 at the very earliest for Switch 2 with TX2. First the interest in the 1000 series cards has to die down some, they're all being bought up by crypto.
Expect Nintendo to treat Switch like a home console, but one that they can't make any smaller like Wii (that was a pointless revision anyway).