If you always use markdown for notes, one workaround is to change all instances of Δ to Δ<span style="display: none">xxxdelta</span>. xxxdelta, or another unique search term of your choice, does not appear in the rendered view of markdown notes.
Drawback of this workaround is significantly less readability in the editing view. If that is an issue, and you don’t do the search quite often, you can apply the <span> tags only when needed, and delete them afterwards.