So if I understand, you have a 10 cell lithium battery pack, and it drives various high power LEDs at various voltages, using multiple buck and/or boost conveters to get those various voltages? Correct?
I REALLY hope you are not tapping the battery bank at different points to get various voltages. This is a disastrously bad idea. Use the the battery bank as a single high voltage source to power all of the buck converters. You absolutely can find 10 cell balance/protection devices. For output voltages that are near to or higher than the battery bank (when it's nearly discharged) you will need to use buck/boost to generate the output, but that's not a problem. If the fully charged battery bank has a higher voltage than some of the buck converters can handle at their input, then find a buck converter which can handle the input voltage, and use it to create an intermediate voltage rail for the multiple smaller low voltage buck converters. Or if the 12 V output one is running directly from the battery bank voltage, you could use that 12 V as the input to the 3.3 V output buck converter.
All LEDs will have a common ground in this case. You have not convinced me that you need multiple different ground points for different LEDs.
thats exactly what im doing lol 10s tapped off in different places, no BMS, charging each cell seperately...
lets say i need to run 4 led's, cell 1, for one led, cell 2 for second led but the higher led needs cell 1,2 and 3 to get to 10+v but the 4th led i wont run from cell 1 or 2 due to current drain but would run from 4,5,6,7,8 and 9 to get to 20/24v
but one COB led likes to be 36v! so i have to run all cells
i know this is confusing somewhat, just trying to save on the buck converter conversion efficency lol