Search internal knowledge across platforms

Does anybody know if there is a tool for searching across different internal knowledge bases?

I’m a senior engineer fully remote and finding that my company (mid-size startup) is experiencing a constraint on knowledge spread due to it being hard to find documented knowledge across all our platforms.

Between Slack, Confluence, Jira, Notion, Google Docs, etc, it gets hard for employees to search everything for the knowledge they need. Does anybody know of a solution for this?