I am a trader in security with MTM as status with IRS since 2014.
I had a losses of $50K as carry forward from previous years.
In 2019 I made profit of 20K.
How to offset 2019 capital gains or other income with carry fwd losses ?
Since you are MTM, there is no carry forward of losses.
If you are referring to $50,000 of Investor losses on Schedule D, you can't apply those to Professional Trader Income, only to the upcoming Schedule D.
Based on your question, it sounds like you are not reporting your Professional Trader activity correctly.