Indeed, hedge funds don't use platforms like Metatrader.
Normally they use a customized solution where funds can have various requirements relating to its reporting, trading style, company structure etc.
The more timing is important (high frequency trading) the more reasonable is a customized solution - typically implemented with C++ for performance-sensitive parts and python for not very performance-sensitive parts.
But we must also say that customized solution can be very expensive so that there are also some professional trading tools that could be worth considering. In this context the Trader Workstation (TWS) by Interactive Brokers (IB) should be noted. It's very powerful and much more adaptable/customizable than most other tools offered.
With TWS you have several risk management tools, sophisticated reporting, an options strategy builder, news, financial data etc. and that all integrated into one single platform.