GsmArena has a fantastical tool for searching and comparing mobile phones. Is there a similar online tool for cameras?
I don't know and I doubt it is even possible and reliable.
There is big difference between DSLR world and smartphone world.
Smartphones are sold and used as is; there is no way of customizing it or upgrading. Except for fancy covers.
On the other hand, DSLR consist of a body and a lens(es) and the lens is the thing that rules the result and lenses are the expensive part of the "garage".
Usually, photographers pick a brand and stick to it, because it is cheaper to upgrade body and lenses separately. High-end lenses last much longer than High-end bodies.
Another reason why DslrArena is not there is because the market is not large enough to pay the service from ads.
There are also very limitted differences between brands in terms of resolution, noise, processing power etc. The things that actually matters cannot be measured and tabulated - handling philosophy and ergonomy. I own Canon 700D; when I am asked to use Nikon I know what I want to do, but it takes me a while to find out how to do it. I bet you, that skilled Nikoneer will have same troubles with Canon.