You can:
- wire individual strips in parallel, this will give you less logical LEDs and will provide “repeating” patterns
- open up SP511e and connect GPIO1 to LED output (this will reduce memory requirements for LEDs) instead of GPIO3 (which is what SP511e uses)
GPIO3 uses DMA and hence its RAM requirements are 5x larger than that of GPIO1. There is nothing you can do about that.
I will not speculate what original firmware does but apparently they do not use DMA if they allow 9000 LEDs on GPIO3. Perhaps the also don’t do a lot of other things WLED does.
I am sorry to disappoint you but GPIO3 is useful for about as many LEDs as you have figured out the hard way.
If you are brave and know how to code C/C++ you can modify the limits which WLED imposes, compile source yourself and hope for the best.
You may want to check this as well.