Discourage Using Garbage As Permanent Landfill

Right now the tutorial pretty much tells you right away to dump your garbage for use as landfill to build a coastline. The only consequences to doing this are the ugly texture of the garbage and the initial pollution from dumping, but long-term it's about as good as dirt or anything else.
IMO it would be more interesting if there was a mechanic discouraging this, either some kind of long-term pollution or making garbage patches not buildable on top of, something like that.
You would then need to create a dedicated garbage dump that you could clean up and burn once you get burners, which is a pretty early tech.

You have a Landfill pollution.
I did dump the garbage on the coastline, and got a lot of landfill pollution. Then tried to take it out of the water which was VERY HARD (no mining underwater). So I started a new game with dedicated garbage dump.
True - you shouldn't be encouraged to dump garbage into the ocean in tutorial

Funnily enough, your last comment is exactly what I do, then switch to incinerators. Long term though I make giant landfills out of my old mines and put a few layers of rock then dirt over the top to make it nice and pretty 😅