I played auto bet on freebitco.in back few years ago with small budget of around 30.000 satoshis. I used Martingdale system and rised funds to around 40.000 satoshis after that I got losing streak and lost almost all the funds. To be honest I would not be confortable to gamble bigger sum.
Entrusting an auto bet bot with a huge amount of money to gamble can be a very big mistake. An bot doesn't have human instincts and experience. It's possible to have some wins using this system but the chances of making profit in the long run would be very small. It's wise of you not to try out huge amounts of money because it might end up being a disaster. It's preferable to continue maintaining smaller sums of money
The Martingale strategy involves doubling the bet after each losing round, so the bets increase so quickly that at some point, the gambler (or bot) simply doesn’t have enough bankroll to place the next bet. Personally, I don’t see the point of using automation in gambling, as it in no way can change the negative expected value in gambling and only speeds up the gambling process.