Maytech is generally pretty solid but that battery is shit.
The cells they use are Panasonic ncr18650bd which only have a discharge rating of 10A. Aliexpress sellers notoriously misspec their batteries. I wouldnât buy from there.
Your total batteryâs discharge capability is the individual cell types discharge rating times the number of parallel groups in your battery pack.
For the vesc/esc switch. The cheapest, easiest, and most reliable method used is an XT90-S loop key.