Coinjoins are pure obfuscation nothing is hidden/encrypted. Not that it would even help as overwhelming majority of Bitcoin users dont coinjoin, and vast majority of LN is using custodians or LSPs so have no privacy. Almost no users are using their own nodes and using private channels (which ironically reduces plausible deniability).

How would you compare volume? The closest thing you can do afaik is compare mcap and capacity. And Monero is almost 10x cap of LN network.

You can't keep your noncustodial btc for long if they can trace it. There are entire categories of mistakes that are impossible to do with Monero.

Bitcoin is just a tool as well not an end all solution. There are many things it doesn't do well and probably never will.