Led Light Flickering Even in On/Off Mode

I have a blue 2-1 switch connected to an LED light in my guest bedroom with neutral. The light began to flicker like crazy recently for no obvious reason. I have tried to set the switch to on/off mode but it still flickers. I have exact same setup in master bedroom, exact same fixture, but not having this issue so far. Any advice on how to debug?

What is the bulb/fixture?

When it’s in the dimmer mode, does it flicker across a range of brightnesses, or just at full power? If it’s just at full power, try setting the maximum brightness below where it starts.

You can also try switching from leading to trailing edge dimming.

Also if it’s not a 3-way switch, you can set it to on/off full-wave and see if that stops the flickering.