While the timing with the copy.fail patches mentioned by a few comments here seems suspicious indeed, I have seen this repeating over the last few weeks: packages.ubuntu.com was hardly reachable on some days, causing apt-get to take forever to update the system. They have been struggling hard recently, it seems.
Best of luck to the people having to deal with this mess on a holiday!
This seems to be pretty targeted, and with the services affected like livepatch and such this could indeed be an actor DDoSing to avoid patches rolling out for copy.fail
Tinfoil hat mode: a competitor wants to exploit copy.fail on some ubuntu servers, and is DDoSing canonical so that they can't update and thus patch the vuln
Double tinfoil hat mode: an attacker learned of my plan to finally update my personal computer out of 20.04 today and is DDoSing canonical so I can't do that and I remain vulnerable to the backdoors they've found.
Seems reasonable to assume it's something to do with the recently publicized exploits. More likely, this could be an extortion attempt by criminals rather than a competitor.
The plot thickens...
This might be the incentive I need to finally purge snap.