My son’s 80cc 2 stroke bogs pretty good at WOT. Fresh 91 octane at 16:1, clean air filter and the exhaust is just the shorty off the back of the motor. Brand new spark plug as well.
I haven’t gone through the carb, but it starts and runs great.
Assuming you are starting with a previous baseline but In my experience, a bog at WOT would indicate a lean setting on the high needle. Try opening the H needle 1/4 turn and reevaluate. If it needs more than a 1/2 of a turn I would want to make sure the carb is clean
Starting a running are the low needle so that is likely okay.
I had this once. Not saying this is your problem but the clamp on the accel cable where it loops into the pedal had slipped, at full gas the carb air inlet was only maybe 3/4 open.