I think the only way to do it is with a wrapped BTC coin.
No Bitcoiner cares about, wants or would even exchange their actual BTC for wrapped BTC to then interact with a smart contract.
The right way to do that is building on
RGB.
RGB is a scalable & confidential smart contracts system for Bitcoin & lightning network. They embrace concepts of private & mutual ownership, abstraction and separation of concerns and represent "post-blockchain", Turing-complete form of trustless distributed computing which does not require introduction of "tokens".
There is a very similar, second such project and to my knowledge, they're also somewhat working together (might be wrong?), called
Taro.
While I'm a critic of the Lightning Labs team myself, I just found out that their
latest blog post is about Taro and they have an alpha release out since September.