A workaround for this could be that I first hire a programmer to suggest a general framework/architecture without revealing details of the calculations.
Finally, I give the job to someone else according to the specifications of the prior programmer. But, since I don't need to explain to him how it works, I can possibly still keep things secret. For example, I can say that this is just a collection of statistics. If he doesn't understand the underlying framework/potential, I don't think he'll bother digging deeper.
You could break your "secret sauce" down into one or more discrete parts. Then hire one or more programmers to code the logic and build a DLL for each of those parts, and then deliver the source code and DLL for each of those parts to you. Then hire another programmer to code the main application, add the DLL(s) to that application, pass relevant data to each DLL, and process what the DLL(s) return.
Since a DLL is compiled code, the main app programmer can't access the logic contained within the DLL unless they reverse engineer the DLL, which is unlikely, especially if you go through Upwork and hire a programmer in India.
For an extremely simplified example:
You want to bring in one-minute price data on a particular symbol. You also want to create a 30-Bar SMA on that data. At the end of each minute, if the price is above the SMA, you want to be Long. If the price is below the SMA, you want to be Short.
Programmer B codes the logic for the DLL. All this programmer knows is she/he will receive two numbers and check to see if Number1 is greater than Number2. If it is, she/he codes the DLL to return a value of "True," otherwise, return a value of "False."
Programmer A codes the logic for the main app and adds a reference to the DLL. This programmer brings in the price data from the API and calculates the SMA. All this programmer knows is that at the end of each minute, she/he needs to pass the current price of the symbol and the current price of the SMA to the DLL, and if the DLL returns a value of "True," the code should put you Long, otherwise, the code should put you Short.
Third-party DLLs are used quite often to calculate and handle all kind of things. Maybe that approach might work for you. If so, it would help keep your "secret sauce" secret.