I suppose it's semantics. The best or most important thing owned or produced by a particular organization." Canon says the R1 is their flagship, so it is." The R5 II will probably sell 6-7 times as many units as the R1.
The Toyota Century is their flagship SUV, it costs $170,000. They'll sell many more Land Cruisers, though...and even more RAV4s.
I think that's when Canon really started pushing the 5-series into the professional realm with the 5DIII. Same AF as the 1D X, which for Canon was a big differentiator for the older 1-series bodies.
For someone who wants more MP, the R5 II is almost a no-brainer. As I've said before, while I'm not opposed to more, the 18-24 MP range is enough for my needs. For me, the 1-series (and R3) is more about ergonomics.