This add-on changes the Add screen to default to selecting the subdeck of the currently viewed card in the review screen or of the selected browser card.
You can download the add-on from AnkiWeb: 1993514119
See CHANGELOG.md for a list of changes.
Please post any questions, bug reports, or feature requests in the support page or the issue tracker.
If you want priority support for your feature/help request, I'm available for hire. You can get in touch from the aforementioned pages, via email or on Fiverr.
Consider supporting me if you like my work:
I'm also available for freelance add-on development on Fiverr: