I'm on GrapheneOS, so they are not enabled by default, but I think on Google certified Android you can also switch them off. Also, besides that, if apps implement notifications nicely, they are nicer on Android, because you can turn on/off notifications per category/channel. Of course, some apps just put everything together.
I was horrified about how many ads my wufe has on her iPhone. I mean web ads in Safari. It's unsusable.
That’s just the internet isn’t it?
Not sure we can blame Apple for that, but I’m sure they could cook up a decent blocker if they wanted.
About Photos: why not disable notifications for the Google Photos app?