You may try to apply $ZSTRIP(yourSegment,"*C")   to remove all non-ASCII characters.
Or just trailing   $ZSTRIP(yourSegment,">C")

https://cedocs.intersystems.com/latest/csp/docbook/Doc.View.cls?KEY=RCOS_fzstrip

That looks good.
But I can not use the index in SQL

. . . WHERE FOR SOME %ELEMENTS(Sample.Person1.AR) (%value......) works as expected.
But
how can I force the  new index  ?

. . . WHERE FOR SOME %ELEMENTS(Sample.Person1.AR.State)  is not accepted
. . . WHERE FOR SOME %ELEMENTS(Sample.Person1.AR_State)  is not accepted
.... ??? what else ??