Generation, or at leat the numbered versions, is an unofficial term that variously gets trotted in and out by various people wanting to describe one thing or another. I don't know if there is an official edict against it like sometimes get issued by any of the companies for when talking to the press but console makers don't appear to use it, historians and academics don't routinely use it, I would wager most of the gaming public (quickfire round name me two consoles from the third and sixth generations, or if that is hard their rough years of being the lead platform. If respectively I said NES and master system era/8 bit era and then PS2 and xbox era instead...), the press occasionally use it but that is sparing as well. It is not a term completely pulled out of someone's arse, might even be logically consistent at some level (next gen, current gen, previous gen are terms routinely understood and used, and abused) and is used in a few places.
The two main approaches are either
1) Order of system releases. If a new system is made that completely obviates the previous efforts then it is a new generation. Weird half measures have existed for a long time (see Amiga, though today most will probably look at the DSi and new 3ds) and some will also attempt to ponder backwards compatibility in this (was the GBM by virtue of its dropped GB/GBC...).
2) What their contemporary console rivals are or might be said to be. This can also mean we have to look at what games get made for it and their relative quality (the Wii had Call of Duty, and while it has its fans for the controls and gameplay it was never really the viable option for anybody playing it on say a PC where you could have kind of got something going on with the PS3 or 360). This gets harder as various things will join at various points (the Dreamcast probably being one of the harder to categorise ones) rather than necessarily be the 5-6 years then brand new console for every major player, even more so in the modern world where relative advancements in visual fidelity, input and whatever else are more minimal/less apparent unless you know what to look for (maybe even going backwards -- wide open levels and large levels seem to be a thing of the past on modern stuff compared to PS360 era and PC of the same timeframe)
Hybrid is a marketing term. There have been any number of handhelds that had some means of playing via TV or a TV out. If all the games play fully in handheld mode, are intended to be played as such and whatever else then it is a handheld. A minor speed boost to make up the relative DPI when you have more power and cooling available is meaningless. Amusingly that would probably mean the super game boy (
https://loveconquersallgam.es/post/2350461718/fuck-the-super-game-boy-introduction ) has a better claim to being a hybrid as it got plenty of processing extras, often colours, multiplayer that did not exist in the handheld mode and a very different experience as a result.
At the same time if Nintendo have in turn abandoned home consoles (which they appear to have) then yeah.
If it is a handheld then that also changes some things for people as the games get harder to compare.
Back to generations.
If it is in a line and we skip minor asides like the DSi and N3ds (both of which do have notable exclusives) and also completely gloss over the GB vs GBC never mind the pocket then yeah it is probably the first in the newest generation.
If contemporaries then the extraordinary length of the current generation means that the 2017 launch will have seen it spend much of its useful life competing against the PS4 and xbone, and as it starts to get a bit long in the tooth and devs start to do throwaway ports of things to it and other devices take focus away...
