A staked collectible goes on sale in the Gacha Machine. When it sells, you get 90% of its RIX Price. Until then, it earns APY in USDT.

Three collectibles go into a pool, earn while they're for sale, and come back as USDT or as collectibles. Pick a chapter to jump to it.
A collectible needs a RIX Price updated in the last 24 hours and a cert, and must fit a pool that has space. Collectibles listed for sale, being redeemed or already staked can't be staked. Spaces free up when staked collectibles sell.
For 24 hours after a pull, you can sell the collectible back to the Gacha Machine, so the collectible stays in the machine. When the 24 hours end, it is sent to your vault and you can stake it.
No. Each stake goes into one pool. Stake again to use another.
For each collectible: the day it sells, or the last day of the lock.
No. It's locked until the lock ends, but it can still sell. After the lock ends, the collectible stays in the staking contract until you take it back from your stakes.
90% of the collectible's RIX Price on the day you staked it, plus what it earned until the sale, all in USDT. For example, a collectible staked at a RIX Price of $100 in a 48% APY pool that sells after 20 days pays $90 + $2.63 = $92.63.
In USDT, to the wallet you staked from. Once a collectible's lock ends or it sells, you claim the amount on the Earn tab in your profile.