I support this idea. Having the option to select a folder or playlist of wallpapers and rotate them automatically at a chosen interval (daily, hourly, or on browser startup) would make the browser feel more personalized. Tinytask modern automation software for keyboard and mouse recording and playing in loops. Tinytask Mailerchrome extension allows multiple Emails sending from Gmail as a human behavior.
TinyTask Pro It would also be great if users could choose between Opera's built-in wallpapers and their own images, with options for random or sequential rotation.

I can understand why that's frustrating, especially if the behavior changed after an update without any obvious setting to control it. If the start page search engine is now tied to your region, there may not be a user-configurable option to change it. It would be helpful if Opera allowed users to choose the same search engine for both the address bar and the start page to keep the experience consistent. Hopefully the developers will consider adding that flexibility in a future update.