Hi @hybridhavoc!
I couldn't find any feature request on our Forum. You can create one here: https://forum.vivaldi.net/category/185/desktop-feature-requests.
The more upvotes it gets, the more likely we are to implement the feature.

In the meantime, have you checked whether there are any Extensions that could help you copy Alt text from images?
You'll find more info on Extensions on Vivaldi Help: https://help.vivaldi.com/desktop/appearance-customization/extensions/.