Section added for Panel missions in the Leveling Guide, which now offer some attractive rewards.
Do your Panel Missions
As rewards, you’ll get the SSR weapon Diablopterux and an SR Miracle ticket. The SSR weapon has a skill that buffs character attack for all elements (it’s essentially a weapon with SSR stats and SR-level assault skill that works with any element, a nice filler until you have a full SSR grid).

The SR Miracle ticket can be used to fill out your main element. See discussion here for ideas. Oberon and Diana are good choices for Wind and Light, respectively, as they provide access to sorely needed debuffs for their respective elements. Healers are also good choices for elements short on them (e.g., Thunder, Dark).