The Sony a1 and Canon EOS R5 are the two best cameras available from Sony and Canon at the moment, and both offer remarkable performance and advanced features that are needed to create nice images.
Both cameras are highly impressive and will be able to perform any function you need them to perform, but the price is also worth considering because the price of a1 is about twice the price of the EOS R5. While it edges out the EOS R5 in some respects, I think it is also good to think about if you are getting into diminishing returns at a certain point. Both cameras are likely more than enough for the needs of 99% of photographers, and if you are not already heavily invested in one system or the other, you can save a bundle and get a nice lens or two by going with the Canon (plus you can seamlessly adapt the vast library of EF lenses). Still, for those already in the Sony system or who want certain features, it is hard to go wrong with the a1.
Check out the video below as Wegener’s gives a full descriptive review about the camera.