Welcome to the forum.
It’s a common issue. It could be axel wrap, transmission, or A/C compressor etc. causing engine RPM raise at idle.
Either way, get used to it. It’s a Taco issue.
My gen three has gotten tremendously better with it. Since the ECU has “learned” driving style.
Welcome to the forum. Only time I notice the engine surge you described is in the morning during warmup.....turn the steering wheel and the engine surges jus a bit.....after it's warmed up never happens again. Don't notice it with A/C on.