Well, in its current form there is no shared security yet but it is the next big feature that is going to be implemented. But there is Juno and Agoric, both are smart contract platforms built with Cosmos (and connected with the Cosmos network), where you can build your Dapp and don't have to host your own security. There is also EVMos, which had a bad start, but it is the same, but it deploys ethereum solidity contracts, but you can execute these with the low fees of a PoS chain.

Besides that from your statement "start from 0 TVL" I assume you find it important that valuable assets are already on the blockchain. So, if you want to build your own chain (and don't want to use a smart contract chain), then you can connect via IBC and this means you are connected to Terra and Osmosis. Osmosis started less than half a year ago with this 0 TVL you mentioned, but today it ranks around #50, so it is before PankaceSwap. The reason why Osmosis is so succesful is its easy to use interface and the possibility to move all these cosmos based assets onto it. The same goes for all chains connecting to IBC. I guess the success of Terra must not be discussed here. So in essence: if you want to build a service that needs TVL, then IBC is awesome for you. If you really need the TVL under your umbrella, in your smart contract etc. then you still have to convince customers to move your funds in your smart contract, but that is the case for all chains ;-)