If you're a new player what other DREAM are you getting within 3 months anyway, time gated or not?
I actually started typing it out then got bored, so heres the short version
Relic is very likely with the ~70 mil price tag and no gating
Mythic is very unlikely with the ~180 million gil price tag and all the *** alongside it (finish ToAU, captain, all the NM's, redo assaults, all the zeni farming)
Empyrean anywhere between easy and unlikely, dependong on weapon: some magian trials have very nice NM's that respawn quick and some take 12 hours to respawn, some weapons are Carabosse quick and some are Chloris/Glavoid *** you, alongside the ~100 million gil price tag
Ergon: easy. the plasm, the stones, ~80 mil price tag can be farmed up between burning Imps, the gating is the 3 months for Legend rank.
Aeonic: involves finishing all of RoV, which involves doing a shitton of the other missions, get the 62k silt to get eschan nef (not difficult) then farm up the 51111 beads required legit? Tall order
Then again, 62k silt is 6,200,000 XP earned in Escha. Thats nothing if you're getting PLed and can get most jobs to 99 in a day. But if you're not getting PLed, thats over 3 jobs from 0 to 99, how long will that take, while doing other things (like making gil)?
All of these depend on how much playtime this new player has per day/week.