The better quality the medal the more progress you get. For example army of one medal or massacre are gold tier medals and will net you 1% each. Lower tier medals will net you less progress. Im averaging about 2% per match with the following medals always collected: First to block Value Hunter Killmonger Blockbuster or Locksmith Following Instructions Sometimes I get lucky and I get a half banked or thrillmonger and get 3%. The medal part is slow if youre not a good invader to be able to get multiple army of one medals per match.

id average about 2% per game Easiest medals to get are First to block, killmonger (20 enemies without dying), multi kills with your super, and kill a high value target