Arm badly pump help !

basically, I get arm pump really really bad. I’m a 15 year old racer on a 125. I really need some other ideas to eliminate my arm pump. Currently I use a 4 Armstrong , cycle before race to warm up, cut sugar out 48 hours before, hydrated, good sleep, great fitness, nose strips to hold nose open for optimal breathing, use cone valves and Traxx shock for bike setup, use all them sprays to prevent it etc. what else can I do? Am I missing something that’s a key?