I don't know if any other GNs find this happening.
I browse the internet quite a bit but I am always very careful untick any boxes that allow third party access.
Nevertheless, I often get as many as twenty or so gambling notifications in my Junk file every day. They mainly offer free spins, whatever they are, as an inducement to join the sites. I should add that, apart from a bit of a flutter with 2p pieces in an arcade and the occasional raffle, I don't gamble.
What worries me is the fact that these sites appear to be totally unregulated and they must be tapping into other sites that have no relevance to betting and gambling. No doubt these sites are selling lists on.
It would be all too easy for me to click on one or more of these gambling sites for a 'free spin,' to get sucked in and end up on the slippery slope of gambling addiction.