It's much easier to achieve privacy on L2 and there are interesting projects doing this already: Liquid Network, Fedimint/Minimint to name a few. Also Lightning Network can act as a privacy layer too.

I am not 100% convinced yet it's worth complicating Bitcoin L1 by introducing hard-core cryptography for this. Plus this space is already explored by Zcash and its Halo2 zero-knowledge-proofs.

Of course, there are coinjoins too and for that I find the WabiSabi method (implemented in the Wasabi Wallet 2.0) quite elegant.