Your concern is more of a sign that you'd be a responsible pet parent. I don't have experience with dogs (rescue or not), but caring for a cat is relatively straightforward and can bring lots of joy. Writing this with a cat sleeping on my lap, who showed up in my backyard a few years ago.
Caring for two cats is even easier because if their human is boring because of concentration, they can entertain each other. Works here, and with rescue dog in the mix too.
Also, if the dog is fond of walks and hikes etc, that’s possibly super healthy for a break from sitting and working. As the joke goes, "Ask me how I know." :)
