In the early days of Facebook, this was a lot more common. It was a novelty, I suppose. My FB friends would post dozens of holiday photos all the time and so would I, and looking back they probably did come over as boastful to friends who didn’t go away, though people did used to say they enjoyed seeing them (maybe they were just being kind
).
I can’t remember the last time I posted a photo, and my friends don’t post many now either. FB to me these days is just a useful tool to find out what’s going on in the area, to check out history groups etc that I’m a member of, keep in touch with a few far flung friends and to have a good laugh about some of the funnier posts on the local groups. I have one friend in particular that I keep “snoozing”, because they post a lot of stuff that’s not particularly interesting to me. Perhaps just do that, OP - take a break from them for a month (and then another one straight afterwards if they’re still irritating you!).