Anyone else getting god-awful MPG lately? Is gasoline quality at stations to blame?

I have a Civic EX-T 2017. Usually fill up at Costco.

Normal average would be 30-32 mpg. Nowadays it usually falls 29 or under… even after I’ve gotten the filter changed!

Also, Starting range after a full tank fill-up would sometimes start around 340 instead of 360. Why? 😟