Many packages at the following website: http://step.esa.int/updatecenter/6.0/snap/ are very slow. Due to this reason it get’s a timeout in SNAP when trying to run the update.
You are right these modules take longer. But it is not the download which takes time, it is the security check by the antivirus software which takes all the time. At least for me.
Maybe you can temporarily disable your antivirus software and try again?
So the zip remark made me check our UTM settings. The UTM scans all packages and therefore takes some time before downloading. Resulting in the timeout. I made an exception for the website and package, now is fast a lightning speed again