Does it make sense to buy a Canon EOS R7?

Hey there!
I own a Canon EOS 70D and I like nature / landscape / bird / sport photography, sometimes portraits.
For nature, landscape and portraits the 70D surely is enough, but for birds and sport photography (cars and motorcycles on racetracks, horses, runners) it's too slow.
Since I own 5 EF-S-lenses I would like to stay in the APS-C format.
The R7 has an internal image stabilizer, R100 and R50 don't.

Does my reasoning make sense? Is there any better option?
What RF/RF-S lens would you suggest getting with the R7?