Modify an existing EA

I have an EA that I need to modify:

1- The EA is working perfectly for all pairs / assets.

except for JPY pairs / Crypto instruments and Gold, the EA is only entering buy setups.

I need to fix it to enter both buy and sell

2- the EA enters any valid trade, no matter if there is an existing trade open or not.

I want to add a feature in the settings ON / OFF

if it is ON then the EA only enters one trade at a time.

for example, if the EA is holding a buy, then it will no longer enter any other buy setup even if the the conditions are met. (until the first buy is closed, then the EA will look for new setups)

and if a sell setup is activated, I want the EA to close the buy setup and open sell

vice versa in case of a sell.

if the EA is holding a sell, then it is not enter any sell setup until the current sell setup is closed.

and if a buy setup is activated, then the EA will close the sell and go for the buy setup.