The danger of 500:1 and 1000:1 is that a tiny adverse move can destroy the account.
The larger the position, the larger the loss from a small adverse move. Beginners should ask how much a 20-pip move costs before asking about profit.
A USD 1000 account opens 1 standard lot EUR/USD. Each pip is about USD 10. A 50-pip adverse move loses USD 500.
Use lower leverage, smaller size, hard stops, avoid oversized news trades and keep per-trade risk near 1% to 2%.