Yet another "Advice for a plan" post

Im relatively new to the game and ive seen alot of people saying that its better to aim for certain db/ds to preapre for trans.allies and the meta shift. So im not really sure which db/ds to go for. Right now i have gaia+1 and im 1 sss away from getting sasha. I have all the allies needed to get tiehr but they arent ultimate yet.

Db/ds that i have 1 ult character for:

Epsilon

Askr

Stigma/atlas

Omega

Pluto

I have eriden but i heard that morgana ia only good for pvp when ultimate. My somewhat of a plan that i had was get tiehr, epslion and atlas and work on ulting them and prepare for helios. Btw is gaint helios falcon teil and helios? Cuz if thats the case i may be able to get it day 1