Autocomplete that matches phrase prefix


I'm trying to achive an autocomplete that will match an exact phrase prefix.

But I don't care where this phrase will be a.k.a in the start of the sentence, in the middle or the end.

For exapmle:

"Brown f" -> "Quick brown fox", "Brown fox" (But not "fox" or "brown")

I tried all elastic options:

Completion Suggester
Match phrase prefix

The only one that suits for me is "Match phrase prefix".

But the problem is the limit of max_expansions (50),
I can't count on a solution that limits me on any number.

Is there any idea how can I achive a working autocomplete without limits (maybe a twick with completion suggester?)