Check the missing 3x speed option in Legend of Defenders

An older 3x image does not give you an unlock condition

One player had seen 3x in a picture and expected it in the full release. Another full-release player could not find it. The direct developer response to “How do you unlock the 3x speed?” explains the disabled option.

There is no announced return date in the replies or in the November 3 update reviewed here. Grinding another castle threshold solely to reveal 3x is not a supported instruction.

What about Wormhole or a black-screen mode?

Players in the Higher speed discussion suggest the Wormhole treasure as a way to move through waves faster while using 2x. That is a separate progression effect, not a restored 3x speed toggle. The discussion does not give a complete current acquisition or upgrade route for Wormhole.

A suggestion to black out the game screen at a higher speed was also only a suggestion. The developer explained that the limit was CPU performance, and said the proposal was something to think about. It was not a published black-screen acceleration setting.

Speed and wave fallback solve different problems

If the real problem is getting stuck above a comfortable wave, use the Auto-Battle Fail Rewind explanation. It covers the setting players identified, plus the absence of arbitrary wave selection. Increasing speed would not remove an enemy-strength tradeoff.

What to check next

You do not need to find another level requirement for this disabled option. Recheck the game's official update notes if a later build announces its return. Until then, distinguish the speed control you can actually see from player proposals and older images.