Hello,
Topics, shared from private category will not available without login.
But I have two idea to achieve it:
1. Use public category and unlist the topic?
Users only can see the topic if they have the link. Works without login if the topic is in a public category.
2. Use page publishing to achieve it?
You can publish the topic even if it is in a private category. So users can see it without login.
For this… first enable page publishing
site setting.
After this you can publish the page with Page Publishing
If your topic in a private category than you have to check the Public
checkbox.
You can use any Slug you want. If you ready click Publish and the topic will also appears without login on the following url.