Discord has its own markdown, so real bold and italic work in messages. Unicode styles still matter for nicknames, channel names and server titles, where markdown is not rendered.
For those fields, a Text Style Generator is quicker than memorising code points. Generate the name, paste it into server settings, and check it on mobile.
Avoid symbols that resemble moderation tools, and keep the name readable at a glance.
Written by FontStyle - more at fontstyle.io.