SHORT: How to tell a coworker "no i'm not interested" in a way that it doesn't turn them into a psycho ?

LONG: So it's been about 6 month since my brake-up and now the local Karens (and at work) are sending me signals or Facebook messages (hi how are you, what's up, - all the usual opening). But what they don't know is that I found my way, MGTOW way...

So, how to nicely tell them to stop bothering me? I love my job and I have to see them almost daily and I don't want things to be awkward ?

I have to reply something, I just don't know what...

Thanks Guys!