Let's ignore the childish behaviour and try to be helpful.
No one's trying to 'sell' you a mirrorless camera - we're simply pointing out that as far as Canon are concerned DSLR's are redundant technology, the idea that the 90d is better than the R6 is a bit weird.
The difference in usability between mirrorless and DSLR's is genuinely night and day (and I speak as someone who currently owns 6 Canon SLR's and one mirrorless).
Let's bust a couple of your misunderstandings:
Battery life?
The quoted battery life for the R6/R5 assumes it's constantly switched on and used sporadically (they're massively underreported). And the battery life on a DSLR assumes viewfinder usage and 2 second image review - but as you've said, you'll use it in live view constantly, and as the 90d and 6d use almost the same battery - it's a simple maths the battery life with the same usage will be very similar.
AF?
The animal eye AF on the 6d is more suited to your intended use than any DSLR Canon has ever made (possible exception of 1dxIII). They might all use dual pixel AF - but the latest R's are a generation newer than the 90d, 2 generations better than the 5dIV
watch
here
Resolution?
Whilst the R6 is only 20mpix, if your intended use is largely video - all that means is that you're throwing away less pixels than you would be from the 90d. The R5 has more pixels, but you don't need them whilst you're shooting video - frankly 20mpix is plenty unless you're cropping heavily.
Macro?
The R6 and R5 do focus stacking in camera
Image stabilisation?
The built in IS means all of a sudden your EF non stabilised lenses become stabilised (very welcome for wildlife and Macro).
Video?
All will give you trouble free 4k video - the R5 starts to become questionable only when shooting 8k
High speed shooting?
The R6 will max out at 20fps if you use the electronic shutter, using the mechanical shutter you're down to 12 fps - whereas the 90d will b down to 7fps if you use live view.
I do hope you can take a few minutes to have a read through this - if not I'm sure it'll be of use to someone else