MakerDAO has to consider many data points to list a new asset, but mainly it’s just token contract safety + admin controls, and liquidity + volume. The first part is not an issue because renBTC already passed, and it’s the same for renZEC. The second part is where renZEC would not be a priority for MakerDAO at the moment, because the liquidity and volume is low.
MakerDAO works by collateralizing an asset to mint a stablecoin, and using oracles to keep track of the underlying asset such as ZEC in this case. If the ZEC price drops, those who have collateralized and borrowed either need to rebalance, or get liquidated trustlessly. If the liquidity for an asset is low, liquidations don’t work, so for renZEC, it wouldn’t be possible to do large collateralizations without the protocol going underwater from a position that had to be liquidated but could not be sold for the amount that was initially borrowed.
And Ethereum gas fees are so expensive these days that MakerDAO also has to disregard smaller assets, because those would not generate enough revenue for the protocol to offset the gas fees it incurs from the liquidation bots and other stuff necessary for the protocol to manage listed assets.
So, either renZEC needs more liquidity on Ethereum through the ZEC community’s involvement, or look for cheaper chains or L2s.
ZEC can be wrapped to Ethereum, Binance Smart Chain, Polygon, Fantom, Solana, Arbitrum, Avalanche, and more coming, and many of these are much much much cheaper than Ethereum, with protocols on them that would consider a ZEC listing.