I just use a custom variable like "StopTrading" and check its value with a condition block before any buy/sell logic. If it's true, the EA skips that trade.
I'm not sure if you can, some MT5 indicators have multi coloured buffers, if you can installing using the MQ file would be the only way and the buffers it installs.
Your logic is correct as far as you are using a negative number on that Constant. That means prce now is in loss that distance in respect of the last open trade.
@l-andorrà Bro, I'd like to consult with you privately through your website, but I noticed the contact form doesn't allow file attachments. Would it be possible for you to share your direct email address instead?