Many times you can solve this by using a wired connection to your network.  WiFi is always slower than wired.   I have resorted to alt, control, delete to get out of an upload that won't finish.  Connect with wire and restart your computer.

Often the speed is better if you update late at night.  To check your speed, go to the speedtest app.

Sometimes you have to turn it off and take it somewhere with better WiFi speed.  Even if it is a public WiFi.  It is only updating the program and not your personal information.   

In my experience, getting faster internet speed has always resolved this.  

You can also manually update TurboTax.  
Manually Update TurboTax for Windows Software (Bas... (intuit.com)

Thanks for the tips.

I've restarted my computer and restarted tt2020 and update seems to work this time.

I don't think it's a connectivity issue/long delay with my computer nor my internet service, as i was able to browse various websites without any delay or issue, but will try speedtest next time if encounter same issue.

thanks