I've played way more Mario than Zelda, so Mario wins almost every time.
I might have to give 3DS to Zelda for A Link Between Worlds and Ocarina of Time 3D. At least if you count remakes.
Mario wins Switch because it has the best Mario game (Odyssey) and perhaps the best 2D Mario (Wonder). Even the Zelda duology on Switch doesn't quite match that to me.

On NES, I give it to Mario. Bros 1-3 are all incredible. The original Zelda was a groundbreaking title, but I hated 2.

ON SNES, also Mario. ALTTP is a great game, but with World + Yoshi's Island, it's two great games against one.

On N64, Zelda. Mario 64 is a landmark title, but Ocarina is one of the greatest games ever made. Didn't care for Majora's Mask though.

On Gamecube, Zelda as well. Sunshine and Wind Waker are both trash, but Twilight Princess is amazing.

On Wii, Mario makes a comeback. While Twilight Princess and Skyward Sword are excellent, Galaxy 1 + 2 are for my money two of the best games ever made.

On Wii U, Zelda. 3D World was good, but BOTW was a masterpiece.

hot take (but i’ll respect it).

The three day loop thing ruined it for me, made it feel repetitive and annoying.

I agree with the OP on each console except for the DS. Simply because I did not like the DS Zelda games much.

Phantom hourglass is probably my least favorite game that I actually played through and Spirit tracks is he first Zelda game I never finished.
Mario on the other hand revitalized itself with the New Super Mario Bros series first entry sparking the Mario 2D renaissance.

I agree on all consoles but Switch... I think Zelda gets that too....

NES: Mario (eventhough I'm also a Zelda2 fan, the 3 Mario games are to good.)
SNES: Zelda just about
N64: Zelda by a whisker
GameGube: Zelda by a wide margin (don't like Sunshine at all)
DS: Mario easy (Don't like the controls of the Zelda's on DS)
Wii: Zelda, but close (actually a Skyword Sword fan, but Galaxy's good too)
3DS: Zelda (Cause Link Between Worlds)
Switch: Zelda (Cause BotW is my favorite game of all time)

I mean, that's how Majora's Mask can be described even without the three-day loop :)

(I kid, I kid. Or do I?)

So it looks like most people who participated in the poll think Zelda had better output on Switch. Thought to be fair, at least as many people though Mario was better or had the same quality as Zelda on Switch?

What are predictions for how the series will fare on Switch 2?

So far Zelda has two Switch 2 Editions and some upgrades while the Mario games have Switch 2 upgrades.

Which series will we see first with a dedicated Switch 2 entry? How many games in each series will we see for this gen?

Switch 2 is in a tricky spot, as TOTK and Mario Bros Wonder released just two years ago, while the Odyssey team is about to release DK Bananza, so it might quite some time before we get a brand new entry in either series.

Given how long its taken them to make TOTK/Bananza I don't think we will see a new 3D Mario or Zelda until the 2030s.