What does Solution to Doom reward?

Solution to Doom gives a choice of Doomsayer's Robe.

Where does Solution to Doom start?

Theldurin the Lost in Badlands offers it.

Its level has not been recorded yet; it shows once a player accepts it with the addon running.

No. The quest exists in Classic Era as well.

World of Warcraft: Forever · quest

A quest in World of Warcraft: Forever, offered by Theldurin the Lost in Badlands. Recorded by 1 player running the addon.

Level, pay and objectives show once a player with the addon accepts the quest.

Item	Given	Item level	Vendor sell
Doomsayer's Robe	as a choice	40	43s 24c

What does Solution to Doom reward?: Solution to Doom gives a choice of Doomsayer's Robe.
Where does Solution to Doom start?: Theldurin the Lost in Badlands offers it.
What level is Solution to Doom?: Its level has not been recorded yet; it shows once a player accepts it with the addon running.
Is Solution to Doom new in WoW Forever?: No. The quest exists in Classic Era as well.

Source: what players running the addon saw in the quest windows; the quest text itself stays in the game. Every quest seen · Badlands