Can u link someone special you have in mind?You can always be the BMS. I would just rather spend my time on my hobbies than constantly checking my battery voltage.
It is high current that can cause weaker cells to sag so your high current needs could be solved by a bigger pack with lots of cells in parallel or a high current BMS. Among the high current BMSs are ones using a separate contactor and current shunt.. That way the current does not have to flow through the BMS. All EVs use that design. You have a lot of choices.