i would say after their permaban, Mirage is G2's worst map, which Fnatic seem pretty strong on. Given how they've picked in every series (or at least a large majority) they've played in 2020, its likely G2 will pick d2.
honestly fnatic have also looked pretty good on d2 as well.
But G2 would probs win on Nuke/Train/Vertigo, all of which which Fnatic have banned before.
That could force map 3 to be one of Nuke/Train/Vertigo.
so if anything, i think fnatic have a higher chance of a 2-0, but if it goes to map 3, G2 will probably take it