My fellow FC member pointed me to various threads on Reddit regarding this issue and one of them seems to have worked for me - I can finally see the patch files being downloaded via the launcher.

See this thread here: https://www.reddit.com/r/ffxiv/comme...035_and_30419/

1. Go to "Windows Security"
2. Go to "Virus & Threat Protection"
3. Go to "Ransomware Protection" and choose "Manage ransomware protection".
4. Click on "Allow an app through controlled folder access"
5. Click on "Add an allowed app" then choose the ffxivupdater file which you can find in the FFXIV folder within the 'My Games' folder in 'Documents'.

You can check 'block history' and if other known legitimate FFXIV apps are being blocked, adding them as allowed app might help to resolve similiar issue.