I managed to finish the mission with all your help and advices. Level 3 mission eliminate criminals from settlement > you get a message they know you're coming (if you use your own ship), and they are waiting for you. Military settlement type. Medium security. One way to do it:
First: Follow Frop's tip: Use Apex directly to the target settlement. This way the message that they are waiting for you will not appear, and when you land at the settlement, it will not be hostile.
Second tip: Follow the Ydiss's Stealth guide with your preferred suit and weapons. Turn off alarms, scout the area, select your targets, etc. Keep in mind that your space in the backpack will be limited. Choose if you want to wear ebreaches or not.
Step 3: Codger, Screemonster and Daniel Cloudsifter among others...Leave the settlement on foot until the "leave settlement" and "mission accomplished" textpops up. Call an Apex and come back to collect the mission reward.
Thank you all for your help and tips:
@Frop,
@Ydiss,
@Codger,
@Screemonster,
@Daniel Cloudsifter, and others
Best regards.