LED brightness is not necessarily linear to voltage. It depends on the COB and emitter design. This is why actual testing using an adjustable lab power supply is valuable. It does not rely on assumptions.
Patio events that utilize lots of lumens needs tighter supervision against "forgot" mistakes than does nightlight glow.
I am envisioning a good looking square red lamp with a round base, and a pair of 22-gauge wires to connect to existing wires.
But if you need a faint glowing pilot lamp with full brightness exterior lighting then what I am thinking of is invalid.