Figuring out how to connect an odd LED strip from OBI

Six years ago I bought 10m of this weird led strip in OBI:

Another thread mentioning this strip in German:

It runs on 12v, 3 diodes per segment, the pins are as described: VCC GND GND DI/DO.
(From earlier testing I found out the middle gnd pins are exactly the same, it runs perfectly with just one gnd connected to the original controller.)

I tried plugging it to Arduino running FastLED (as ws2811) and NodeMCU v3 running WLED with a 12v power supply attached, sadly with no success. It seems to respond to commands but flashes random colours on each segment. It doesn't react to turning off and after many sent commands it settles on one "combination".

I doubt anybody has a similar led strip, but I would really appreciate any tips that would help me to get it running.

Please provide a wiring diagram; a reasonably sized photo (around 300 kB) of a hand-drawn one is fine.

Here you are.

The NodeMCU generates 3.3 V logic which is somewhat unlikely to reliably drive that strip anyway. You would probably need a 74HCT14 (two inverters cascaded) to provide adequate data levels to the strip.

Thank you for your answer. I will have to buy those chips anyway (I need two), so I want to make sure that I don't throw any money down the drain and buy the ones that solve my problem.
The WLED forum suggests three different levelshifters:

What worries me is that it doesn't even work with arduino at all with 74Ω or 55Ω resistance on the data pin.

I also tried testing it today. It shines different colours, turns on only the second segment or doesn't turn on at all. However, one thing that seems to work (sometimes) is the set length.

It probably does, but the 74HCT14 is likely to be more readily available - and cheaper FWIW - and perfectly functional. The speed of any of the 74HC devices is more than adequate for this purpose so that is entirely irrelevant to the choice as is bidirectionality so the more expensive and difficult to obtain TXS0102 is an absurd choice, however the common "bidirectional level shifters" using little FETs are completely inappropriate.

Now do note - the series resistance in the data line mounted at the beginning of the LED strip is also essentially irrelevant. It will not by any means the reason it does not work. Whatever the problem is, it is elsewhere.

A decent picture of your connections to the LED strip and the firss few of its LEDs is in order. Also your code, given that you have read and followed the instructions as to how to post code.

And here is the code I used

#include <FastLED.h>
#define NUM_LEDS 84
#define DATA_PIN 3
void setup() {
    FastLED.addLeds<WS2811, DATA_PIN, GBR>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);

void loop() {
  fill_solid(leds, NUM_LEDS, CRGB::Red);;

Tried testing different colour sequences, that also didn't help. Today I'm going to buy those inverters and use WLED to get it working.

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