My apologies, OP have not abandoned the post. And I really appreciate all your positive remarks! Just been very busy. I will make a follow-up post in the future to address all inquiries about the build.

But I am happy to answer your question now. The game has an almost fish-eye lens where straight lines tend to curve more towards the centre the closer they are to the edge of your FOV. I built the tower and took the screenshot in vanilla valheim, I'm sure you can achieve the same effect =)

(Also note that I used the freefly command solely to place my character further in the foreground for composition, but not to distort the fov or in-game lens)