Perhaps, some adjustments to your gameplay might shorten that time even further alongside a better set of equipment. Assuming One-Handed melee with a Shortsword, Imperil plus Vital Strike, the former in all Arenas the latter against Schoolgirls, improved my clear times (in Isekai) drastically. No Shadow Veil, no Haste (costly), and more Block and Parry (through gear and proficiencies - Assimilator training) could be assistance as well. Spirit Stance management and Orbital Friendship Cannon. If you have been using Imperil and Vital Strike (also "discarded" those "auras") and your Arenas still take that long...better level up fast and visit those WTS stalls or the auction : ).