I like OperaGX for its customizability, and I really enjoyed Chrome mods which allowed for customization of the cursor when using the browser. This suggestion is essentially a merger of those two: adding custom cursors to OperaGX. I feel like this small detail could add so much to the modding scene in terms of creativity. On top of this, the extensions for mouse cursor customization from other browsers and extensions are quite rudimentary, allowing for capitalization on those who wish for an improved form of this kind of feature.
I want to specify that this suggestion is for OperaGX, not for the standard Opera browser.