The lines are fine, but please tell me the last time team won the cup with only ONE RHD.

I dont think handedness matters in the money ball era, but they also probably take one in the draft this year

You failed to answer the question, which does not surprise me.
"...please tell me the last time team won the cup with only ONE RHD"

Literally the most irrelevant question. Why do you always have such an attitude?

The lines are fine, but please tell me the last time team won the cup with only ONE RHD.

Literally the most important question!
"...please tell me the last time team won the cup with only ONE RHD"
There are not any that is why you are ignoring it and diminishing the importance of it.

Skyraider112
Shibbal18

First, a defenseman playing his off hand is vulnerable to strong forechecking because he has to use his back hand to advance the puck or shoot the puck behind the net increasing the likely hood an attacker will collect the puck.
Second, when playing the point he has to use his back hand to stop the puck from leaving the zone when a puck is shot around the boards.
Third, replay Tuch's empty net goal v Vegas. Eichel could not keep the puck in the zone and was embarrassed surrendering the puck so easily as he was on his back hand.

I only did the last five years of cup winners.
Remember last year all four finalists had balanced LHD with RHD.
NHL head coaches are a lot smarter than I, the winning coaches seem to like to have balanced defenses.

2022 Colorado 3 LDH 3 RHD
CALE MAKAR
DEVON TOEWS
BOWEN BYRAM
JOSH MANSON
ERIK JOHNSON
JACK JOHNSON

2021 Tampa 3 LHD 3 RHD
VICTOR HEDMAN
RYAN MCDONAGH
MIKHAIL SERGACHEV
ERIK CERNAK
JAN RUTTA
DAVID SAVARD

2020 Tampa 3 LHD 3 RHD
VICTOR HEDMAN
RYAN MCDONAGH
MIKHAIL SERGACHEV
ERIK CERNAK
KEVIN SHATTENKIRK
ZACH BOGOSIAN

2019 St. Louis 3 LHD 3 RHD
ALEX PIETRANGELO
COLTON PARAYKO
JAY BOUWMEESTER
JOEL EDMUNDSON
VINCE DUNN

All balanced defensemen.

2018 Washington 4 LHD 2 RHD
But Carlson and Niskanen played 51 minutes per game so the RHD played nearly a full game.
Include the 5 minutes that Orlov, Kempny, and Orpik played the PP, Washington only played 4 minutes per game with two LHD.
JOHN CARLSON
MATT NISKANEN
DMITRY ORLOV
MICHAL KEMPNY
BROOKS ORPIK
CHRISTIAN DJOOS

But you can do the additional research to find a team that had one RHD.
Five years is sufficient to make my point.

Lets say in an alternate reality Cale Makar and Josh Manson were both LHD playing the right side. That would make 5 LHD and 1 RHD. You don't think they would have been good enough to still win the Cup, even if all that changes is the handedness of two of their D-men?

Shibbal18 I am not surprise that you would agree with such an outlandish comment, but Skyraider112 you are much smarter than this to ignore facts.
Sure you can have any alternate reality you want but Makar and Manson were both RHD.
The fact is the last five Stanley cup winners played with effectively 3 RHD.
Dream on all you want, make up any stories you want, pretend the last five cup winners did not have 3 RHD, ignore all of the facts, make up your own alternative facts.

Now let me try to explain to you WHY coaches want 3 RHD and 3LHD.
In the defensive zone, when a defenseman is on his off side, he needs to use a back hand to clear the zone, or use his fore hand to shoot the puck behind the net and attempt to clear out the opposite wing.
I have watched enough hockey to know, when when a defenseman tries to clear the puck by wrapping around the boards, it inevitably ends up on the attackers stick at the point.
I hope you have noticed how often this maneuver fails.

When a defenseman playing his off hand in on the point he needs to collect the puck on his back hand then transfer it to his fore hand to make a play.
Let me remind you of the Vegas game.
Jack Eichel was playing the left point, his off hand side.
When Tuch charged the point, even a player as talented as Jack could not control the puck and Tuch was able to steal it, rush down the ice and seal the victory with an empty net goal.

Please stick to the facts and ignore your alternative universe, coaches prefer to have 3 LHD and 3 RHD.

FINALLY to answer your ALTERNATIVE UNIVERSE.
While Colorado won the series in 6 games two of them were OT, "That would make 5 LHD and 1 RHD. You don't think they would have" lost both of those OT games?