You’re running on blacktop/concrete, right? Not in the grass or something?
@RedPen , it’s important to note that “one run” is not bashing for as long as your LiPo lasts. A “run” is a speed run that takes seconds. Then a cool down.
Take your speed pinion off and put your gearing back to stock. The stock pinion is 16t. That’s for normal use! All bashing use with the stock system. You MIGHT get away with a 17 or 18t, but you must monitor your temps, and if you’re running 6s then you need to do it before you hit LVC on your high MAh LiPo. Or you can easily roast motor #4. The speed pinion is just for speed runs. One at a time. Maybe two on a cool day. Again, these runs only take seconds, so heat doesn’t build over time, and even then needs to cool down.
And if your motor is getting hot enough to roast marshmallows all the time (dude!!!) then your temperature sensor must not be working. What kind did you install? What kind of temps are you seeing? You mentioned frying three motors in a row but didn’t mention the temperatures? The stock electronics only protect the ESC for thermal shutdown, they won’t keep you from frying your motor. Buy an infrared temp gun for cheap and check the motor temps in the middle of your pack at the least or sooner until you know what kind of temps you are building. Cool off if it’s 180° or so. That’s Fahrenheit, man. If it hits 200° it’s dangerously close to roasting for good, and if you hit those temps regularly the life is shortened a lot.
https://www.amazon.com/Etekcity-Thermometer-774-Temperature-Accessories/dp/B0B71HFH9K/ref=sr_1_3?crid=122YIZQAPBRAW&dib=eyJ2IjoiMSJ9.B8IdPmfLXhOV8DKXq9KlfoWqozKwkKDfAfvMJxBX2RVj6u3v8ELjn-0W-_lsbfxjoUHEiG9QhVLsQOq-TGv-t5Zqa8asDklA2pYOtq-SZrgbkteQ5FxQV3iUsIAkpwARdEOmlFWhJBcYg_lcH5mN6yb1rhd5zRhnI6lc5ViVPaFFIfPHoo3h4QXYJYHcQKW2VkxBQKeBxNvTtQphkAQYdyOn3FsmpfHozo3kc2-tXXM.QkNul_iNjgTKRZ4UXP99_72ACn11i3XmAfMbu54-Wjw&dib_tag=se&keywords=Infrared+thermometer&qid=1726623126&sprefix=infrared+thermomete,aps,117&sr=8-3
Like others said above, if you want to run it to the extreme for long durations many here will be happy to help you spend



for a system that can handle it. Your stock pinion (16t) and paying attention to the motor temperatures
before your marshmallow is finished roasting is key.
I don’t think it’s a good idea at all to say this until he is a lot more experienced in not roasting motors.

When I was a noob I came very close to frying my
Max6 system in my Mojave. I think I was running a 19t pinion.