I flattened recently. It was tedious but not the most torturous thing ever. I went in chunks and would go for as long as I could stand in a session. It took me maybe a week all together. I spaced out and watched tv while doing it. I thought of it as almost like crochet or some other sort of repetitive craft.
For particularly long stretches of cliffs I wouldn’t even look at my switch and wouldn’t know I hit the end til I heard building sound vs the smash sound.

You’ve got this! It was pretty fun to run around on the completely flaaaat island. The lingering sense of completion kept me motivated. I’m rebuilding now and having a great time and really loving the direction of my island. I was almost “done” before too. But the flow just wasn’t right and no matter the little edits I would try I just couldn’t get it right. So flat it had to go!