if only there were some websites, an Ads Library or Ads Transparency Center of some kind, where people could easily verify any or all of this

This is the exact billboard that came to mind for me, I drove by it daily for a long time

https://old.reddit.com/r/Israel/comments/1bmdy03/someone_in_...

There were many other similar ones, especially on the smaller digital ad spaces that were basically just TVs on the side of roads. And those ones were more specifically calling for empathy for the deaths occurring to Israeli people during the war on Palestine

There is: https://adstransparency.google.com/