V2 of my battery counterweight for the Oculus Quest 2 Elite Strap, more secure and doesn't require velcro. The clips mechanically attach to a battery cage. This mod will triple your battery life to about 6 hours, and the counterweight will vastly increase comfort by taking pressure off your face. Overall cost should be about $25 (~$20 for battery, ~$5 for cable)
The battery chosen was the Aukey PB-N83 (Basix Mini) 10000mah, not just for it's ideal counterweight mass, but the uncommon pass-through charging feature which means plugging in the battery will fill the Quest 2 first, so you can leave the battery connected to the Quest permanently. Link to amazon price tracker: https://camelcamelcamel.com/product/B08H8KKW5Q
You will also need a 1.5foot USB-C to USB-A cable like this: https://www.amazon.com/dp/B081MSD21C
The curved rail that sticks out of the battery cage can be slipped into the clips by bringing both clips towards the center simultaneously.