There is no Bitcoin coinjoin in the world that can give you the Tx obfuscation that Monero gives you.
Discussion
If you transact purely in monero, then monero is better privacy than bitcoin+coinjoin. Nobody is gonna argue against that.
Now if you are suggesting taking your non-private bitcoin and swapping it into monero and then back into bitcoin instead of using bitcoin+coinjoin It does look like bitcoin-monero non-custodial cross-chain atomic swaps are possible, but I've not used it.
https://eprint.iacr.org/2020/1126.pdf
But can't really compare. The ring signatures in Monero are all enforced and participants are not required to be online and coordinated. Also there is no real concept of a post mix where the anon set reduces periodically for a transaction as every tx has CT and several mixins
A Monero transaction between Bitcoin wallets will obfuscate the money trail. It's a viable solution to breaking the Tx link on your Bitcoin. Better if the vendor you're trying to transact with accepts Monero directly of course.
Chainalysis claims they can de-anonymize a significant portion of Monero transactions. I'm rather dubious toward that claim.
It’s a true claim actually Atomic swap to Monero provides an effective solution for Doxic change outputs. But if you are swapping into Monero, you would be well advised to not swap back immediately. Best to wait a little bit before doing so to avoid the guess first heuristic.
You would also want to avoid sending the same amount back as this will allow simple amount correlation. Monero's opaque blockchain has privacy advantages but whirlpool does a good job breaking deterministic links and providing forward looking privacy. You would need to determine your level of privacy requirement and transact accordingly. If you want to stay in BTC the whirlpool is best solution and swapping doxic change to xmr is effective for that use case. Also liquidity is def an advantage in BTC's favour.
My preferred way to convert Bitcoin to Monero is actually to buy hashpower on nicehash and mine to a pool. That way I get freshly minted XMR sent to a wallet that nobody knows exists yet.
Isn't Monero a shitcoin?
I've been using it since 2016, and no.
It's fully decentralized, worked on by an ad-hoc community of developers just like Bitcoin.
It's more decentralized than Bitcoin because it can ONLY be CPU mined. You can't run RandomX on a GPU or ASIC. You can't build an ASIC to run RandomX because you're basically reinventing all the features of a CPU.
Okay...so its only usavle for CPU like desktop or laptops?
There's still some ways of fucking up monero and leaking your IP address with certain light wallets, but yeah better privacy at default.