Assuming the holy grail is 100% winrate, while being very profitable of course, then yes such a system almost exists. More like 80-99% winrate exists.
The perfect trading system does exists. The only problem is can you get the perfect trader to trade the perfect system?
The perfect trading system is highly discretionary and thus there will generally be a few losses that occur because of the traders false interpretation of the information and/or see things and opportunities which don’t really exist.
But yes, it does exist.