Working what I call spikes, your 8-10" trees with little upper branch structure;
Keep a round or two handy, fell ONTO the rounds. Keeps a bunch of the trunk off the ground.
I'm no firewood maven, but doing volunteer work and watching newby's, it's WAY too common to see folks all bent over but NOT having the dogs in the wood. Now you are bent over AND holding up the saw. The idea is to support your upper body with the top handle and lever the saw up/blade down with the rear handle, pivoting on the dogs.
I'll repeat: Keep the saw dogs on the log! Now you are supporting your upper body with your arms/hands/the saw dog/trunk. It's not hard to work bent over "for a while" if you are supported. You should at least have a saw with metal dogs.
If you aren't "wondering how to pay for your next meal", A pro class saw is one of the few "investments" you can buy new.
Coming battery tech may change that a bit. But compared to health, back issues a pro saw is cheap anyways.