is it possible to filter program name or id when exporting activities through api?
either rest/v1/activities.json or bulk/v1/activities/export/create.json it's returning mixed activities for all campaigns
There’s not, only by the asset itself (e.g. in the case of Send Email, the numeric Email ID).
You should be prepared to filter activities on the client side; one advantage of the paginated API in this regard is you can stream data and remove unwanted entries on the fly. Still, the data will go over the wire.