"Stop-losses are very important in investing but I'd recommend always executing them manually at market rate."

No, no, no, no ...

You do not ever want to insert a market order[1] ... the market can be manipulated and high frequency traders can buy/sell your public market order at an artificially low/high price.

The answer to getting "stopped out" is not to insert a market order - it is to create a fill-or-kill at a specific price or other more specific order type ...

[1] https://www.marketwatch.com/story/this-is-why-you-never-use-...