Theres no reliable way to counter these decks other than giving some usage to cards like Path to the Peak, which doesnt let Eternatus or Dragonite use its abilities
Also, there is an indescribable tactic of putting 3 self-destruct switches in the side deck , winning the first round with the side effects of Shimochi, then changing all of them to self-destruct switches In the past, Shimochi was literally a burn deck that used recovery effects to deal damage, but now that the meta has accelerated, it has a stronger one-turn kill tendency than burn decks
Most of the time, however, theyre probably just going to be blocked or removed themselves
(I know the phrase is "melody" but "dirge" fits the concept better)
If you pull a chase card, put it straight into a penny sleeve and top loader immediately, assess it properly, and decide whether the math works before it gets handled again