Features like newsgroups, chats and RSS feeds have their place, but they're not what most people care about in an email app. These days, most people want only stuff like having their calendar and contacts other than email in an email client. So release a minimal version of Thunderbird called Thunderbird Basic alongside side Thunderbird with just these core functionality.
Benefits to the users:
Impact on Current Users' Experience:
This proposal won't affect existing Thunderbird users. Instead, it will be released as another variant alongside Thunderbird, similar to how Firefox and Firefox Developer Edition coexist. Those who prefer a basic email experience can install Thunderbird Basic, while others can continue using the full-featured version.
Acknowledgement:
The idea is inspired by F-Droid release a simpler version called F-Droid Basic and Debian packaging a stripped-down version of KeePassXC with only core features.