It should be better than other mods, that do similar things that I have looked at since it just uses linked belts, to link to a normal balancer made with belts and splitters on a hidden surface. I specifically avoided using API such insert_at_back
because such API would require running every tick for UPS reasons even though it would have been easier to do.
I did look at some other balancer mods before making this and they were using these API https://lua-api.factorio.com/latest/LuaTransportLine.html and unless you wanted real slow belts those API would have called quite often which definitely will effect UPS.
TLDR;
It should be more UPS friendly than other similar mods.