I imagine that it’s a well trodden path seeking out a satisfactory code or syntax highlighter for wordpress.

You can, just about, paste colour-formatted code from some editors into the wp text editor  (e.g. SSMS to Outlook Email to WordPress), but it creates a mess of the HTML.  Not pretty at all.

Current preference:

• Crayon Syntax Highlighter.   Nice to use;  line numbers; expansion to new window; code-block size limits.  The main drawback seems to be that the colouring is rather random.