Three different numbers
Separate the broker's minimum deposit, the strategy's practical minimum account size and your own maximum acceptable risk. They answer different questions.
Position sizing matters
Some strategies need enough account equity to scale positions gradually. With very small balances, minimum lot sizes can make the actual risk percentage larger than intended.
Leverage can hide the capital requirement
High leverage can allow a small account to open large positions, but that does not mean the account is adequately capitalised. The same mechanism that increases exposure also accelerates losses.
Use drawdown to work backwards
Estimate a stressed drawdown rather than relying only on the historical maximum. Then ask whether the resulting monetary loss would be acceptable if it occurred soon after funding.
Start size is a risk decision
For speculative automated trading, use capital whose loss would not impair essential savings or household finances. A low advertised minimum should be viewed as an access threshold, not a recommendation.