Should I turn Tradovate snapshot P&L off?

Usually leave it on. It is the fallback Copilink uses when an open Tradovate account has no live quote: it asks Tradovate for an account-wide balance snapshot, one account at a time, and shows Reduced protection. It is slower than live quotes and each update uses one Tradovate API request. Turn it off only if you run many Tradovate accounts and want that API budget for trading, and you accept that P&L-based limits will not be checked for those accounts whenever there is no live feed. Copying keeps working either way.