you can still talk to friends, but not about the vacation

Hmm… interesting. I think I'd still yes, but as I really enjoy talking to friends about things I currently do, rather reluctantly (and not for a very long one).

With your explanation, I can see how you get to that interpretation, although mine would probably different (mainly because I associate post with A: showing it to a larger group simultaniously and B: having a picture or video (but that's just due to my personal media usage)).
I think I might place the line between a small group of friends you tell it and a larger public Discord server(?) as that mostly feels like the difference between privately talking and posting it to a bigger audience, but it's complicated.

it’s more 'would you go on a vacation and just enjoy it, or do you only want to go on vacation so people know you went?' yeah, that makes sense. I see. I mean I would definitely go to a vacation to enjoy it (and not to show it off or something, in fact my last Instagram post is now over a year ago and I don't really use Twitter or other personal social media like that). But not talking about it would still be hard as I basically talk to people every day about what I'm doing, where I'm going, what projects I'm working on, etc. So having to stop sharing that would be different to my usual way how I spend time with people. (But I'd just do it all afterwards, often in vacations I don't have much time anyways to talk to people about it and just catch up later in a longer talk.)