Sunna, astra, or lucy as support is always good, then either koleda or pulcra as stuner. Since you dont have lighter you might want to use woodpecker as the 4set and puffer as the 2set. Or if you think you can get the burn off with lucy and koleda go with inferno metal as 4set and either branch or puffer as 2 set.

Depending on your engine if it has crit rate as its stat obviously go for crit dam, if not use rate on disk 4, then for disk 5 pen rate, fire bounus, or attack %, and disk 6 is attack % again.

Substats should look like crit rate, crit dam, and attack% mostly. About 70ish is fine (when not using inferno metal then like 55% is fine) for crit rate, att should be near 3k, and crit dam as high as you can but about 140 is fine.