A 16-gauge cord is fine for that vacuum.

You’re good.

16-gauge at 25 feet for 7 amps is nothing. That cord is rated for 13 amps continuous, so you’re barely over half capacity. Voltage drop is negligible at that length.

The internet loves to scare people into buying 12-gauge cords for everything, but unless you’re running a table saw or a compressor that spikes hard on startup, 16-gauge is perfectly safe for a shop vac.

One thing: make sure the cord is fully unrolled. Coiled up, it can heat up faster. But that’s true for any gauge.

Save the $20 for a new pack of filters.