Treasure Golem and Arena invitations questions?

I’ve been playing the Vita version of the game for several days straight and it’s been at least three days without getting an Arena invitation or seeing a treasure golem?

My character is level 96 and I’ve maxed out better duty rewards, spoils of war and I have level 9 loot hoarding.

Am I doing something wrong? If the chances to get these are so low… do they get any better in Siralim 2?