I agree what Von Sparq says.
I think that a lot of server administrators often remove chunks after they are generated.
I usually deletes the chunks too to renew resources near spawn point.
Moreover, I faced an issue unluckily before.
The issue is that the chunk has error and cannot be loaded well.
The only way I can do is to delete the chunk to regenerate.
If I have to delete chunks after updating to 1.18,
I may need to face the risk of not blending well in the regenerated chunk.
Can confirm.
I have the same issue.
That means we cannot trim near the edges of 1.17.1 after upgrading to 1.18.
Will Mojang enhance the blending feature in the future to prevent harsh chunk borders if we delete the chunks in the edges of 1.17.1 terrain if the world is upgraded to 1.18?
Because it is not easy for us to remember which chunks are in the edges of 1.17.1 terrain and many players want to delete chunks without worries such as having error in those chunks or before upgrading from 1.18 to 1.19 in the future.