R3II in '26 and R1II earliest in '27/28?

[Copland]

Is it realistic that Canon will release an updated R3 with the R6III’s sensor in 2026, while the R1 won’t receive an update until at least 2027 or 2028?

Or is it the case that, since the R1 is now the flagship, it will also be given priority, especially in the context of a megapixel increase?

 

[padam]

The R3II might get a global shutter to compete with the A9III, while the R1II could move to a higher megapixel stacked sensor like the A1II.
Whether that's going to happen any time soon, who knows, but both product lines will continue.
But then there is this article: Canon: No Plans for High Resolution R1 so maybe that's not what they are planning.

 

[Stig Nygaard]

Well, by history (Canon 1-series "flagship" history) the only thing I'm pretty sure of is that we will see R1 announced in late 2027 to mid 2028. Because that is a camera Canon always want to make ready for the professional sports-shooters at the Summer Olympics. The 1-series' release schedule is tightly bound to that event.
Canon doesn't seem to believe that high resolution is needed for the sports photographers (and personally I tend to agree, though I'm not a professional sports photographer ).
I don't know if R3 was the start of a new series. Maybe the R3 was a one-time model to try some new technologies (Eye-Control, Smart Controller and stacked sensor), before rolling it out in R1 and R5II? But if we see a new R3, I cannot imagine it getting the sensor from R6III. I would expect it to get a stacked sensor again.
I don't think Canon thinks global shutter technology is ready for prime time photography yet, but if we get it, my bet is it will be in the R1.

But that is all my guesses without knowing what kind of technologies Canon has cooking in their labs. Or their strategies. But my guess is probably at good as anyone else not having inside knowledge