I’m only getting 12 points for Apex Arenas Ranked

How is it working as Intended.. in ranked BR you can literally get 40+ xp for doing very little and simply surviving into the top 5 with 0 kills or damage whereas I played a ranked arenas game last night where I finished with 9 kills, 5 assists, 10 knocks and over 2500 damage to receive 13 ap as a reward. It's virtually impossible to grind to get up the ranks if you are a casual player and seems that if you score badly on the initial ranking challenge or don't have a consistent squad to play with and get many consecutive wins you can't get the ap to rank up. I initially thought it was linked to kills and damage but it seems the ap system is actually broken