With the new Fleet Thorn mechanic, is high-Tier Atk Disso impossible now?

Since Attack Dissonance provides almost no damage, Thorn is basically the only way to kill Fleets. But with the new Fleet Thorn mechanic, how are we supposed to deal with them now?

Second Wind and the Nuke mastery aren't enough, especially at higher tiers where Fleets spawn much more frequently.

Has anyone found a reliable strategy, or is high-tier Attack Dissonance no longer viable?