EDIT: SOLVED

EXPLANATION: my domain has .app TLD like @kai-zaphosting told.I found that Google owns .app and there is some HSTS policy , again like @kai-zaphosting explained ( u shld read that ) and it just redirects all http requests directly to https , and my page was http not https, so i was not seeing a page. And the curl methods given in the comment along with a few more confirmed that request was being served succesfully on http and https was the culprit.
To get my website working, i just firstly pointed my domain to ip and generated certbot certs and then setup certs for the VPS Nginx config and then tried visting, and WOOOH it WORKED.

Thanks a lot @kai-zaphosting :)

This site can’t be reached

mywebsite . com refused to connect.

ERR_CONNECTION_REFUSED

When i try to ping , it works , but 100% packet loss

IP is resolved when i check via public DNS checker, idk what is wrong , support hasn't replied yet.

I have 4 domains registered, and only one is working . All have exact same settings . Tried pointing all to same IP, still only 1 particular one works for some reason.

Please help

EDIT: Porkbun is only serving as domain registrar , website is hosted on custom VPS by Azure