The 2021 stimulus payments are not being used for food and gas right now, and those two things are about as inelastic as you can get for demand anyway, thus the 2021 stimulus has little to do with inflation right now.
Gas prices peaked in June, thus why inflation spiked. Gas price affects the cost of every tangible good, and no Fed action is going to have any significant impact on the demand for/price of gas.
Gas prices are up almost 50% over a year ago. Diesel prices are up over 60%. That's what's driving inflation. That, and housing which is a supply issue and also inelastic in demand because whether own or rent, people have to live somewhere. Either home prices go up or rent goes up, or both if supply is too low.