But then it would be a replacement for the RP, not for the R.
Despite the headline, I don't see it as a "replacement" for either camera, more as a new category. The R was a big disappointment to many people - no IBIS, a gimmicky swipe-bar that no-one liked, a repurposed sensor from the 5DMkiv, and mediocre ergonomics (compared to other Canons). So I think Canon will try to wipe the slate clean and base the design on the far nicer R6.
If CR's source is correct in stating that the camera will "sit below" the R6, it's unlikely to have a better or higher MP sensor than the R6. IMO, it's more likely to keep the R6 sensor but dispense with features such as IBIS, in order to keep the price below the R6.
For the subjects you mention (landscapes, flowers, insects) the R6 is perfectly fine, and has a sensor which performs at least as well, if not better, than the one in the original R. We can all only guess at the specs of the so-called "R replacement", but if you want more MP and "extra reach" for insects and flowers, the R7 will most likely prove to be a wiser choice.