You may find what you are looking for here:
https://www.mql5.com/en/articles/4566
https://www.mql5.com/en/articles/8226
https://www.mql5.com/en/articles/3540
https://www.mql5.com/en/docs/customsymbols
      
      Modeling time series using custom symbols according to specified distribution laws
      
    
  - www.mql5.com
 
        The article provides an overview of the terminal's capabilities for creating and working with custom symbols, offers options for simulating a trading history using custom symbols, trend and various chart patterns.
      
    
Hello folks!
I have several custom symbols in my MT5. I would like to know if there is a way to update them automatically using MQL5 or Python. I already have software that keeps my historical data up-to-date in a CSV file. However, I’m still updating it manually within MT5. Is there a way to automate this?
Thanks!