Unfortunately the AF isn't quite as good with adapted glass on Sony. It's fine for slower moving subjects but for wildlife I'd certainly want a native like performance.
On R5 EF glass do seem to adapt very well indeed.
None of the systems are quite there yet on their own.
Sensor - Sony
Shorter Primes (14mm to 135mm) - Sony/sigma
Longer primes (200mm+) - Nikon/canon
Zooms - Sony/tamron/Nikon
IBIS - canon
AF - I think the top three are about equal now give or take.
EVF - Sony
Body size - Sony
Ergonomics - Nikon
Mechanical shutter - Sony (1/400s flash sync is nice)
Software features - Nikon/Panasonic
Adapter support - canon (for EF glass)
If someone can combine all these into a camera system that'd be perfect for me