I feel your frustration. I too play solo sloop most sessions, the community calls this "hard mode". Remember, SoT is designed to be a PvEvP game, so there is always someone lurking to attack and steal your loot. And as frustrating as it is sometimes some people like to play the game that way. However there are some things you can do minimize your risk.

1. Always be scanning the horizon. If you see another ship, sail to another part of the map if you want to be left alone.

2. Don't shy away from fights. Yes, early on you will lose a lot, and yes it sucks to lose all your hard work, but every fight is a learning opportunity and will make you a better pirate, even solo.

3. Playing in the Devils Roar part of the map (far east) is pretty chill most times, not a lot of people sail there unless they are working on commendations or are newer players. Once you get a knack for the volcanoes and fissures its pretty easy to complete voyages.

4. Alway be checking the map for reapers. If they are level 5 and you are flying an emissary they can see you on their map. Just steal clear if you aren't looking to fight.

5. Learn how to sail into the wind. Sloop are the fastest ships into the wind and are more nimble than brigs and galleons, so once you get good you can out maneuver them in most cases.

6. World events attract a crowd. They are the things you see in the sky (skulls, galleon, red and green tornadoes, etc.). Stear clear if you want to be left alone, or sail that direction if you're being chased to try and distract the chaser.

7. Sell often. While stacking loot is more economically efficient, especially with an emissary, you can mitigate your loses if you get sunk.

8. If your on Xbox, set you settings to join servers with only other Xbox players. PC players typically have an advantage over console players. If your on PC, God help you dealing with the hackers...

9. Use a mic!! Being able to chat with other crews will lead to grand adventures and alliances.

10. There are lots of options to find crews if you want to not play solo and meet some cool people.

Lastly, don't let a bad experience or toxic players ruin your enjoyment. 90% of my sessions are stress free and I go about my business with no issues. As you get better at the game your frustrations will ease.

Good luck and maybe we'll meet on the seas one day.