Do I understand correctly - you want to capitalize words like remix and skit?
We don’t need $rrplace - better change (capitalise) each word separate with $replace:
$if($rsearch(%title%,remix),$set(title,$replace(%title%,remix,Remix)))
$if($rsearch(%title%,skit),$set(title,$replace(%title%,skit,Skit)))
These should be separate statements in case both words appear in one ETI. I’ve first tried with a if not condition, but if the first word matches, the second one would not be replaced.
EDIT: $if is not necessary - if “remix” is not found, the title remains unchanged.
$set(title,$replace(%title%,remix,Remix))
$set(title,$replace(%title%,skit,Skit))
EDIT2: I think, searching for “skit” is risky - you will not search in English titles only and even those could contain names with “skit” in the middle (certainly not to be capitalized)
For “skit” I would recommend:
$if($rsearch(%title%,[^:alpha:]skit),$set(title,$replace(%title%,skit,Skit)))
If there’s a alphabetic character preceding “skit” - no capitalization