Just to clarify, the idea of this flatcoin concept is not to be a Bitcoin replacement, nor a proxy token. It's purpose is to allow for a stable transition regarding volatility. A flatcoin can be a mean for the mass of people to migrate to bitcoin by avoiding both fiat inflation and bitcoin volatility.
In the white paper, you defined the Virtually Hybrid Token VHT, which is a stablecoin based on the dollar, and it is not much different from LUNA, and the guarantee is the BTC pool, which wll be bad if the Bitcoin reserve decreased severely, which made it impossible to guarantee the stability of the exchange rate. How will you solve this problem? (If your clients have a lot of VHT and the value of Bitcoin decreases, you need more of it to maintain the price of the stable currency.)
So instead, decentralized ideas exist, such as L-USDT as a sidechain on Bitcoin, or centralized solutions as I mentioned above.