You’re assuming the O2 sensor is the reason for your problems. I doubt seriously that it is. I wouldn’t touch it without first running a curve on its output signal. If it were out of spec it’d be tripping a fault code.
I’d’ start by assessing the engine’s overall condition with a compression test. Since cleaning the throttle body seems to have helped, that would suggest to me that you had some carbon buildup. That would in turn suggest that perhaps the engine is tired. By “tired” I mean cylinder wear and loss of tension on the piston rings, compression and/or oil wipers.
Check the compression and post back.