As cws very rightly points out, there is certainly no requirement in principle that codeshare partners extend privileges such as priority boarding etc to the other airline’s status holders, and certainly not that the operating career treats the customers of the marketing airline as the marketing airline would treat them on their own metal.

imagine CX pax flying on a ba short haul connection. Should they be entitled to free food and drink onboard the ba flight because on cx they would have got it?

imstead, reciprocal perks are negotiated by the airlines and here do not include priority boarding.