How a spot grid earns, in plain English
A spot grid places buy orders below the current price and sell orders above it. Each time price falls to a buy level and then rises back to the matching sell level, one slice completes a cycle and the bot records grid profit. Exchanges charge their normal spot trading fee on each filled order; Bybit's Spot Grid FAQ says there is no separate fee to create the bot.
Grid profit counts only completed cycles. Total P&L also counts the coins the bot is holding at today's price, plus fees. If price falls and stays down, the bot holds coins worth less than it paid, so total P&L can be negative while grid profit is positive. If price trends out of the range, the bot can end up holding mostly one asset and stop completing new cycles.