I like your recursion method, which strictly should be faster than bruteforcing… But be aware that UE4 has a C+±level node for calculating the minimum of a float array. I do a similar system for my grind rail splines and I simply subtract the location of all spline points from the actor position and get the resulting distance, add it to an array, and grab the minimum to find the nearest point index. It’s mathematically slower than recursion BUT since it spends less time in the blueprint-C++ interop layer doing conditional checks, you may find it’s faster to bruteforce it.
Just in case you cared.