Can I add a direct link to a topic in sidebar

Support
2

I believe you can here

The image shows a sidebar menu or navigation panel from a website or application, displaying various sections such as Topics, My Posts, Review, Admin, Filter Topics, More, Users, About, FAQ, Groups, Badges, Upcoming events, Docs, Customize this section, All categories, Configure defaults, and Tags like UploadVR, RoadToVR, and Meta-Hmd. (Captioned by AI)
The image shows a sidebar menu or navigation panel from a website or application, displaying various sections such as Topics, My Posts, Review, Admin, Filter Topics, More, Users, About, FAQ, Groups, Badges, Upcoming events, Docs, Customize this section, All categories, Configure defaults, and Tags like UploadVR, RoadToVR, and Meta-Hmd. (Captioned by AI)864×1920 109 KB

This Customization > Theme component though think will give you more options