FF didn't bomb in 2020, they over performed in 2016.
In 2016, FG, in their eternal arrogance, went around asking everyone to "keep the recovery going", while a vast number of the population were still feeling the negative effects of 5 years of crippling austerity. Those people went "what recovery, do you think we're fucking idiots?"
FF got a bounce from that, as you know, people have short fucking memories and couldn't remember that the crippling austerity was mainly down to FF in the first place, and proving FG right in the process.
They returned to their now middling level of support in 2020.
Does that speak to the intelligence, or ignorance if you will, of the electorate? Therefore the political parties in question playing us for fools.