It’s an older home and its plumbing / drain lines may not have capacity (or might be partially contaminated) to handle high pressure / large volume of water pumped into them from the toilet or from the washing machine.
If you have clay pipes underground (or any type of aged waste line) they might be deteriorated to the point where power rodding clears the path for a short period of time only. If the pipes (or their section) are heavily deteriorated and roots have penetrated your drain lines you might need to repeat rodding process on regular basis or replace that compromised section.
Water backing up from the drains is usually a sign of a clogged waste line and not a plumbing vent problem. Depending on the design of this old plumbing system flooded pipes might be blocking vents and cause gurgling noises.
You might want to hire a plumber with a camera to check the condition of your drain lines and decide further action after that.
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