I've noticed that I've not had many PWPs suggested to me by my villagers recently? Is there a way to make them ping me more? Or is it completely random?
This method is great for resetting pings, though I'd suggest a bit longer of a wait. I found that 15-20 minute waits are better. It's longer than the mentioned but I found that every time I check, after waiting for more than 15 minutes, I have a ping. Whereas 5-10 minutes, sometimes no one pings no matter how much I walk around them.
Added tip for the diving trick: find one of your peppy villagers, preferably in a more secluded spot and dig holes all around them to block them. Dive into the ocean for (I've found a 15 minute minimum works best), run back over to them. Rinse and repeat until they ping for a PWP.
Also, when you're doing the diving trick, make sure to carry around nothing but flowers, bells, tools, or something that isn't furniture/clothing. It makes your villagers less likely to ping you for gifts or for trades, thus giving you a semi-higher chance of getting a ping for a PWP.