Never used a R6 I/II so no comment on that except when comparing R6 with R5 sensors you should up or down res. one of them to compare apples to apples.
The r5II is supposed to have a worse sensor(new stacked design, seems al stacked sensors are a bit less) regarding noise and DR. But it's so little I've not seen a difference when I switched R5 to R5II.
Some well meant advice for Jeff. Looking at your photos, seeing the conditions you often shoot in(far away in combination with haze, heat shimmer etc.), even if you buy the newest, most expensive camera you will not get much improvement. I think I've shown I can take a sharp picture with my equipment but if the conditions are against me even my gear(i.e. me

) fails to get something decent.