The last few days before election day, there was a big increase in spam with canvassers sending out texts. As @LongHiker said, it has nothing to do with the app. You can turn off notifications for the spam so you never see or hear of them unless and until you check the spam and blocked section. In notifications, turn off the slider for for spam protection. You have to have categories enabled for this.
I use Google Messages for a very long time (I own Pixel as well) and this app block most if not all of junk! Some may show up in the inbox if your messages app, however when you open it, you have the option to report as spam. As previous person mentioned make sure spam protection is selected in the app's settings. I also use Phone app from Google which has other options for blocking scam calls.
