I have lost 5 times some small accounts (less than 100$)
And one little big account (400$) in trading.
I think that $ 100 is more than enough for day trading.
And about how much you lose your account, that's a risk you have to accept. Receiving is not only surrendering to what you have got but, starting again to improve your trading skills. From your experience of losing a sizable amount of accounts, I think you are able to understand what you are missing. Learn what went wrong when you experienced these losses, don't be afraid to start again, because you lose when we don't try again. As we continue to want to learn from our past experiences, I believe you will be able to find a bright spot to solve a problem that is currently happening, such as you losing your accounts.
Because we all must have experienced these times. The more stable you will be in trading the more you learn from the experience you get. Because, if you experience a problem that is almost exactly the same, you will already know how to solve it and it is possible that the experience you got before can solve new problems that will come.