I heard that Ubuntu Snappy Core can have only snaps.
I am only a hobbyist with a laptop, never used Ubuntu server or Snappy Core.
According to the sudo snap refresh speeds that I get, updating a snap-based OS will make your life like accidentally executing sudo rm -rf / if there are lots of updates.
How did you deal with it?
“No” in answer to “Is updating Ubuntu Snappy Core painful”.
I having difficulty decyphering what the rest of your actual question is.
Are you implying snap refresh is slow for you due to your slow internet connection, or that the store downloads are slow while other things are fast?
Bear in mind snap refreshes automatically in the background. So as long as your system has a connection to the Internet, the refresh will happen each time the system checks. You can of course force refresh or postpone the refresh.
Also note that Ubuntu Core is more tailored for single-use devices, like digital signage, routers, gateways etc. Not so much for general purpose computing like laptops/servers.
also note that snap packages by default only update binary deltas between two packages, only the few changed bytes between two snaps are downloaded at all and then applied as updates.
