It used to work, but due to recent update in the app, the support to HTML was removed.
For details, SmartThings Android App Updates - Version 1.8.13.22 (Mar ‘24) - #12 by AlejandroPadilla
Here is how it is being displayed after the breaking change related above…
If the reason is really security, it would be great to have a whitelist of safe tags and attributes that could be used.
Everything else would be sanitized and wouldn’t show up.
Suggestions
Tags: table, thead, tbody, tfoot, tr, th, td
Attributes: style, colspan, rowspan, align