Is the icon you want to use already available in your Slack workspace? If not, you will have to upload it first in the admin section. It should be accessible at: yourslackurl/customize/emoji.

Otherwise the proper syntax for naming Slack icons is :emoji_name: Please note that you must replace spaces with hyphens or underscores.

Navigating the setup for the Bot Icon in Slack can indeed be a bit puzzling. It sounds like you've tried various approaches already, but sometimes simplicity is the best bet. Have you attempted using the emoji name wrapped in colons without any additional characters or spacing? That method usually does the trick.

Also, have you ever considered creating custom icons or emojis using an ai vector generator? It could be a fantastic way to add a unique touch to your Slack workspace and make your conversations even more engaging.

Keep experimenting, and don't hesitate to reach out if you need further assistance.