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Hi mate, unfortunately I can't answer for your question. My led's are connected to external power source. I have about 2 m of lights with 12V and WS2811 driver.
And because I have an external power and signal it will take less power than with driver in handle like original one.

https://ledlightsworld.com/blogs/led-lighting-knowledge-base/how-to-select-appropriate-transformer-for-12v-led-strips (look at step one ;) )

Hopefully that was useful.
Also I just make a copy, you can ask designer (Adafruit) they have a nice channel on YouTube.
I wish you successful calculations ;)
Have a good day mate.