Electronic – Creating a RGsB to RGBS converter

If money is not of concern, you could consider a passive delay line such as these.

They claim that they can make delay lines with up to 30:1 delay to rise time. You are asking for about 13:1. Their standard products are only ~4.5:1 though so expect longer lead times and even higher prices.

Perhaps there is some other way of doing this than involving a delay...

The reason for splitting at each 5m is because the tracks on the strip are not that wide, and if they have to carry the current for any subsequent strip, they would heat up, as well as drop the voltage, and eventually blow up.

Both option 2 and 3 in the first picture will work, but make sure that the power supply and the driver can handle at least the total absorbed current 12A. For safety sake, I would multiply that figure by 1.5 just to have a safety margin, and make the parts have a longer life. Optionally you can have 3 or 6 separate drivers, with all inputs driven by the same pins of the ESP8266.