Hi and welcome to the forum:
First of all, it will help us to help you if you try to explain what the purpose is behind your photography - without that creative context is it hard to provide relevant technical ideas to support your intent. From your choice in lenses, I would suspect you are looking at landscape and portrait work, but that's a guess.
However, looking at your choices I can already suggest that this does not make sense. The R7 is a crop-sensor camera which means that for wider angle lenses it crops the image, resulting in a field of view equivalent to shooting with a lens 1.6x the actual focal length. Essentially, you would be buying a 15-35mm f/2.8 lens and producing results that could be just as easily be achieved on a full-frame camera with a 24-50mm f/4 optic, and will also cost you a stop of dynamic range. Furthermore, the dynamic range of the R7 is already very weak, resulting in noise in photos from a relatively modest ISO value. See the chart below from a site called Photons to Photos, that geeks out on camera technology:
The table represents the maximum ISO value that each camera could use to achieve a dynamic range of 6.5 stops. The R7 is second from the poorest, while the the R6MkII is over twice as effective and just above the boxed in R5. There are also issues with the readout from the sensor at high frame rates, and bottlenecks throughout the data bus. If you don't shoot high frame rates or shutter speed it might not be an issue, but the mechanical shutter sounds like a tinker's cart, which drives most people to use electronic shutter, which is where some of the issues start.
So, without knowing the purpose of your photography, from a purely functional point of view, I would suggest getting two R6MkII bodies: they have better sensors, fabulous focus and tracking, better buffers and more solid build. That also means that the control layouts will be the same, which will not be the case if you move to a mix of R6II with any other bodies - the R7 and R6 each have different control layouts, which may not sound significant, but it can be annoying when trying to get to know the controls without thinking.
I would couple that with the RF 14-35 f/4L lens - which has benefits of being significantly smaller, lighter, cheaper and allows the use of conventional screw-on, standard 77mm filters, compared to the RF 15-35mm lens f/2.8. I can't comment on the 70-200 for your purposes, except that is it a good lens.
A review of the RF 14-35 to which I would concur.
https://www.youtube.com/watch?v=qvoNbZN0aH4&t=5s: with regard to lens correction - this lens has been around for a couple of years, and all PP software has the corrections for RAW and JPGs are corrected in-camera and those are now correcting down to f/4 effectively.
You can purchase both lenses and bodies via the Canon Refurbished site, where Canon sells at reduced prices gear that may be new but overstock, opened box but unused, show or demo models - all 'good as new' and with a Canon warranty.
RF 14-35mm $999: Shop Canon Refurbished RF14-35mm F4 L IS USM | Canon U.S.A., Inc.
Canon EOS R6II $1.699: Shop Canon Refurbished EOS R6 Mark II Body | Canon U.S.A., Inc.
