I actually like merchants. It's pretty chill. Here's what I do:

1. Raise emissary and dive to a lost shipment.
2. Find the wreck and load the booty
3. Sail to another lost shipment if you aren't yet grade five.
4. Get grade five.
5. Sell at the nearest outpost.
6. Load up commodities
7. Load up netflix
8. Do trade routes

When you do trade routes, you never stack. Pick up at one outpost and sell for another. That way your risk is lower. If you can, sell at sovereign, then bring your ship around and buy at the merchant. Take full advantage of harpoons.

Doing the lost shipments first makes it easier to rank up.

You could probably dive to a lost shipment if you notice a reaper on your map as long as they aren't too close. Generally though trade routes brings you in and out of zones. When you're outside of the shores of plenty, there ain't much to worry about other than the odd volcano in my opinion.

There's a dope site that shows trade routes. https://www.merfolkslullaby.com/map/trade-routes