How can I add a Prefix Index?

I migrated from Prisma, and I have a column with

varchar(2000)

varchar(2000)

varchar(2000)

varchar(2000) which I indexed with

@@index([columnName(length: 191)])

@@index([columnName(length: 191)])

@@index([columnName(length: 191)])

@@index([columnName(length: 191)])
but the introspection schema didn't seem to recognize the index length:

columnNameIdx: index("TableName_columnName_idx").on(table.columnName)

columnNameIdx: index("TableName_columnName_idx").on(table.columnName)

columnNameIdx: index("TableName_columnName_idx").on(table.columnName)

columnNameIdx: index("TableName_columnName_idx").on(table.columnName)

is there a workaround to set the index length? maybe with raw sql?

Thank you in advance.