is it possible to beat 6m with my servants?

First, you should raise a taunter to avoid Ibaraki's NP (Mash especially). You need also a survavilist like Cu FSN to survive the last of the 15 turns. So the backline should be Mash - Heracles (Bond CE if you have it) - Cu FSN.

For the frontline, Jalter as a damage dealer (Ushi CE LB so you need another one) + Hans (with his 2nd and 3rd skills leveled up) + Waver Support (Golden CE LB).

Dealing the whole 6M will be nearly impossible but surviving should be in reach if you have the servants I listed (But I don't see them in the screenshot)

Test this setup on 2 BP. Jalter + Drake + Waver on front line. Build NP on first wave. By the time the hands are full bar on NP either use Drake NP. Next is Waver NP for one turn stall. Put Mash in the sixth row with Golden CE (it is recommmeded to level her), plugsuit her to Drake and use taunt and invicibility to her. If you are lucky, do NP brave on Jalter. That time you have done at least 1.5 damage to Ibaraki.

As for fourth and fifth row, level Cu to have access on his guts and CA Hassan for his evade. If front line fails, they can stall as much as they can. You don't really have to invest in their skills for now for it just makes their cooldown lower.