How to get rid of wasps nesting under huge deck?

This site has some ideas that might be able to help you:

https://gardenerdy.com/how-to-get-rid-of-wasps

Hang temporary plastic sheets to enclose the area and then hang "no pest strips" you might need more than one.

See if any of these will work: https://www.doyourownpestcontrol.com/wasp.htm

Good post from Holly, very informative.

Looks like you are not able to get to the nests to physically remove them or at least spray.

The idea of attracting them sounds do-able, but may dangerous depending on where the trap is placed, people could get stung by getting too close to it.

The best way to go is hire professional help, they have the equipment and the protection to handle this situation.