Should I pressure wash my deck first before staining?

Yes it must be totally cleaned and dried before applying the stain.

Yes. Clean and dry. Home Depot has some great deck stain that will last approximately 4-5 years.

Yes

Yes, pressure washing your deck is highly recommended before staining it. Pressure washing can help quickly and efficiently remove any dirt, debris, grease, pollen or mildew that may be lingering on your deck. Not only does this make the staining process easier and less time consuming by cutting down on the amount of prep work required beforehand, but it also ensures that you get an even stain application without having to worry about any contaminants hiding under the surface.

I read it here: https://sunsetpressurewash.com/pressure-washer-all-you-need-to-know/