I found a tiny plains island well off the coast, ocean on every side. Tried to build a lighthouse, but I'm not very good at building so it looks really bad. That said, there was enough room for 2 smelters, 2 windmills, 2 blast furnaces, 4 coal burners, a bunch of beehives, and a small farm. Also 8 cloudberry plants were growing there that I saved.

Spent several days and a couple thousand stone expanding the farm, but it otherwise had room for everything I wanted.

Map seed aJUfrS903Q

https://steamcommunity.com/sharedfiles/filedetails/?id=2756574041

That is the seed and location, if you want to try it out for yourself.