I strongly doubt that Nintendo will release two systems, and even if they release one, it
absolutely will not be some powerful console that attempts to compete directly with Sony and Playstation.
My reasoning is as follows:
(1) Nintendo has never (NOT EVEN ONCE, ZERO, ZILCH, NADA) successfully competed directly against Playstation and Xbox
N64 was a direct competitor to PS1 and got wrecked
Gamecube was a direct competitor to PS2 and got wrecked
Wii U was a direct competitor to... PS4 and Xbox One and got wrecked
In contrast:
Wii didn't compete with PS3 and Xbox 360 and was a runaway success
Switch didn't compete with PS4/Xbox One/PS5/XSSX and has been a runaway success
I think the chances of their next system even being stronger than a PS4 Pro are remote.
Could argue the only reason NES and SNES did well is because Nintendo didn't have to compete with Playstation yet
(2) Nintendo Switch seems to be what the company was really aiming for with Wii U
If you look at the basic concept of what Wii U is, it's really just the Switch but without the ability to be
truly portable. It's hard to know but presumably either the technology or the technical thinking (or both) weren't there to enable them to make something like the Switch at the time. Alternatively, maybe the Tegra X1 was just too expensive to consider based on Nintendo's typical approach of putting out a relatively weak system to ensure profits on each unit from day one.
Along these lines, it seems weird that Nintendo would fail an entire generation to finally find the perfect secret sauce (that is, the Switch) only to chuck away the Switch idea and gamble again. Besides, the Switch isn't just a system for casual players. There are lots of great games on the system, and it's loved by hardcore gamers too. In that sense, I think coming out with an upgraded version of the Switch with some other QoL features (I'll let Nintendo work those out) would not be risky in terms of casuals not upgrading.
I remember some friends who had a Wii back in the day and it was never used beyond as a party prop when friends were over. It was pretty shit as a single player console to play
actual games. I think most people would agree with that in hindsight. It was essentially a long-running gimmick that was priced so low that it was basically an impulse buy. In contrast Wii U had some good games, it was just a shit/pointless console that nobody would realistically want.
(3) Nintendo has literally combined its portable and home console hardware/software development teams into one big team
They did that a while back around the time when the Switch released. That's a pretty major organizational overhaul and not something the company would do if it had planned all along to dive back into having a separate "home" and "handheld" console. I think the aforementioned structural change was and is intended to be permanent. Maybe they would change it back if the Switch failed but the Switch clearly hasn't failed.
Also, I don't think the Switch Lite is evidence of them being willing to split up the consoles. Switch Lite is basically just the current gen version of the 2DS vs 3DS. It has its place but it's essentially the same machine. I don't think it constitutes anything like splitting up the consoles (at least in the way you're suggesting they would make a 15-20tf system.
(4) One of the big reasons to put out a powerful console would be to win back major third party publishers but....
Honestly, it doesn't look like Nintendo gives a shit. It's a case of "
if you build it, they will come". Look at all the third party games that are now on Switch (that you wouldn't expect) after the console sold gangbusters. Who would expect games like Doom and Witcher 3 to be ported to Switch? Sure they're not the best-looking or performant versions of those games by any means but clearly the devs/pubs couldn't ignore Switch.
I think it'll be the same next generation no matter what Nintendo puts out, as long as it sells well. Nintendo has never gone begging for third party support and probably never will.