We don't have synonyms for surtitling yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are subtitling and uptitling.
(n) :
A translation of a segment of the libretto or other text or sometimes a brief summary of the plot projected onto a screen above the stage during a performance of an opera or other similar performance sung in a foreign language; a supertitle.
(n) :
A translation of a segment of the libretto or other text or sometimes a brief summary of the plot projected onto a screen above the stage during a performance of an opera or other similar performance sung in a foreign language; a supertitle.