I use a Canon 80d but I think nikon is better value. For wildlife generally the longer lens the better. I think the bare minimum and most budget friendly lens would be a 250mm lens and the 55-250 IS STM is a good starter lens. But 400mm is definitely more ideal for wildlife, they just cost a lot more. You can get good shots with a 250 you just have to get a lot closer than you would with a 400mm.
Once you get all the fundamentals down of how to operate the camera and what a great picture needs to consist of you might get to a point where a "cheaper" lens starts to hold you back. Not saying you can't get great shots with a "cheaper" lens but more reach and higher quality glass will result in sharper images and shallower depth of field. But you can still get good pics with a 250mm you just have to get a little closer and separate the subject from the background as best you can.
Most cameras are decent enough, the lenses are what will make or break you. I think the most versatile Canon lens for wildlife is the 100-400 is ii. It's what I use but it's very pricey. I actually bought it before I was any good at taking pics. Knowing what I know now, I could take much better pics with a 55-250 than I could the first couple years I had the 100-400.
So my recommendation for a good budget starter Canon outfit for wildlife would be an 80 or 90d and a 55-250 IS STM. You could go a little cheaper on the camera with the rebel line. The quality is roughly the same but the button layout on the 80 and 90d is much better.
Check out
@Alyssa-Bee 's photos in this thread. I think she uses a Nikon and a 300mm lens which is a good budget option and some of her pics are excellent. If anyone's on a really tight budget I feel like you get a little more for your money with Nikon.