Launching Now Assist Virtual Agent (Chatbot) from a Button or Link on Portal

I want to force the Now Assist virtual agent to launch a topic via a button or link in the portal.

My research indicates that it's possible to force the virtual agent chatbot to launch a topic via links or buttons, as found in the knowledge base and community resources.

https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB2321890

https://www.servicenow.com/community/virtual-agent-nlu-articles/can-i-force-a-virtual-agent-to-use-a...

https://www.servicenow.com/community/virtual-agent-nlu-articles/toggling-virtual-agent-chat-client-u...

Is it possible to force the Now Assist virtual agent to launch a topic via a button or link in the portal?