My idea here is this Scenario on boss phase to make it faster : Eternal goes S3 then Chain Link then Valentine 6* Transcend with 6* AP Talisman to Burst 3 bringing the 2 DPS to dual atk, unfortunately I couldn't do it since I don't have 6* Val yet and I'm lacking 6* CP talismans so I had to use that Talisman for Drakhan to at least do the Eternal S3 then Chain Link.
BGM:
kiss of death (Darling in the Franxx but is it okay if it's lofi )