I struggled with the same search and ended up getting the AirGradient DIY Pro Kit Pre-Soldered. Not quite plug and play but the steps to get it up and running are fairly straightforward. Just plug parts in, drop some firmware on, and go. Curious what other suggestions are out there because I would still like something simpler!

https://www.airgradient.com/open-airgradient/shop/#!/DIY-Pro...

I use a 'LEVOIT air purifier'[1], and it has a PM2.5 sensor that works w/ Home Assistant out of the box through the VeSync integration [2].

1- https://smile.amazon.com/gp/product/B08L73QL1V 2- https://www.home-assistant.io/integrations/vesync/