I wrote a snippet to filter out the AI from Atlassian Jira, I reckon it works on their other products too but it was mainly Jira I was focusing on.
This removes the AI button as well as the stupid underlined words you can click.
atlassian.net##+js(aeld, /^(?:click|pointerup|mouseover|mouseout)$/, , elements, .acronym-highlight)
atlassian.net##span[data-testid="atlassian-navigation.ui.conversation-assistant.app-navigation-ai-mate"]
atlassian.net##span.acronym-highlight:style(all:unset!important)
atlassian.net##button[data-testid="platform-ai-button"]
atlassian.net##div[data-testid="highlight-actions.ui.popup-target.popup-dialog.popup-wrapper.popup"]