Why do you want a 72v Battery?
Be careful, batteries declared as 72V deliver peak 84V (20s) and will fry your VESC
The 75300 is for 18s max
Trampa rates it for 16s max to allow for spikes.
Most used Batteries with the 65161/65162 Motor here are 14s or 12 s, more than enough to get foiling.
If you buy a battery pack don’t go to low on Ah, otherwise the pack will not be able to deliver the necessary A, depending on the cells used in the pack you need a certain amount of parallel series. And cheap packs = low current even with many parallels
I build a battery pack of 12s6p Molicel P42A which gives me at the moment 55 min of pure ride time. As I fall frequently I suppose ride time will get even better when I have less starts.
I got everything I needed to build the battery pack, including Cells, Ni strips, cables, connectors, smart BMS, shrink wrap etc. and even the spotwelder incl. LiPo for 500€ (and hours and hours of study). But beware, building a high power battery pack is dangerous an can set your house on fire