Why is he being polite to me especially when we haven’t talked or had any other conta

He could be bored, lonely or wants to chat with you again.
Covid has severely disrupted so many people's social lives, dating attempts and employment.

*cracks knuckles*

He may be feeling lonely, sure. But then again, I used to be chatting to my ex crush for ages, before i realised i actually LIKED him. I then practically ghosted him for a year because of my nerves.

Whatever I implied, you didn't hear it from me

So what are you saying ? That he likes me but he’s shy ?

Yep, thats what i'm saying.

Then again, he might just want to reconnect, but also consider other possibilities

Does he really need a reason to just be nice and congratulate you? I mean, what's wrong with it?

Would it be desperate if I started to talk to him again ? Also he replies to instagram story usually if I have posted a life event. So far he has reacted to my life events three times (for example to congratulate me or offer condolences). Idk why would he care about my life events since we have never dated and aren’t even friends…

Idk I thought guys go out their way to be nice to a girl who they aren’t friends with if they’re interested in her…

Not really, if you respond as a friend, you might get hints or something. Then again, he might just want to reconnect, but you should totally reply normally.

Sometimes yes, not always the case tho. Just being nice in general and congratulating you isn't really going out of his way tho, just a kind gesture.

What kind of hints for example ?

He sent me a private message by replying to my instagram. He could easily keep it moving and not text anything…

I mean, I ghosted my crush so aha i have zero clue, maybe like i dunno an interest in you like first asking questions like how your day was?
If he replies hella quick, then it might be a sign, or if he'd rather talk about you or ask questions to make you talk to him?

Yeah but he decided not to. He actually decided to talk to you which means he cares at least to some extent. Whether this is just as friends or more I really don't know as idk how close you are with him.

Idk if this was coincidence. One time I was mainly the one who asked him questions and he replied to them and he also asked me back same questions. Then I diidn’t talked to him for a while and he then posted to his story ”ask me questions”
He had never posted that earlier to his stories.

I’m not close eith him at all he knows me through mutual friends but that’s all. He knows some basic info about me.

Well he's trying to talk to you now so he either wants to just befriend you or wants something more. I'd say keep talking to him and see where it goes.