I've uploaded a video without the widescreen patch having been applied (fresh installation):
https://streamable.com/qzz1t5
Here are two screenshots for comparison:
View attachment 271022 View attachment 271023
Initially you can see that the screen ratio is fine. When I run the game as "last played", the "NDS Bootrap" splash screen and the 3D elements of the in-game overworld are narrowed horizontally.
In case I activate the patch, I think that the behavior is unstable. In my latest tries, when I run a game with the aspect ratio set to 4:3 as "last played" it runs in widescreen instead. Of course widescreen stays forever and the "aspect ratio" option vanishes from settings.
I should clarify that every issue occurs when I run the game though the "last played game" option.