Advice: Hauling canoe on FGRV
A kayak is about as effortless as it gets on the water. I am not an athlete, nor even in particularly good shape, but I can paddle a kayak for hours. It's an amazingly natural and efficient means of moving through water. I've canoed and I've rowed, and a kayak is nothing like either.
It does require some dexterity to enter and exit a kayak, but once in, it's very comfortable. I introduced my mother to kayaking in her late 70's. She mastered the basics quickly, and her stamina lasted 2-3 hours exploring a local lake.
I get old waiting to get anywhere propelled by an electric motor. A kayak can run circles around anything using a trolling motor without breaking a sweat, and never any range anxiety.
I guess if you've tried it and it didn't work for you, then I've nothing to say, but if you've never tried it, you might be as surprised as I was the first time I hit the water in a small kayak.