I had an experience like this ages ago, like I am talking way when ARR was fresh fresh and I wasn't even out of high school. Two people were RPing during a raid and kept trying to include me despite me clearly not wanting to due to not responding or even acknowledging their existence outside of actually playing the game. I eventually told them that I really wasn't comfortable RPing with them, especially mid raid and they understood and stopped entirely.

You really just have to open up about it, most players will understand or at the very least stop without a word if you make it known it's bothering you. And you kind of have to, cause for some reason in FF14, the RP community(atleast the exclusively in game RP community), is weirdly pushy and weird and don't know of that fact half the time.