Crypto tribalism aside, you got two technical points fundamentally wrong about the cryptography: 1) snarks are fast now. It takes 3 seconds on a pixel phone for Zcash.

2)The decoy based approaches Monero uses are subject to all kinds of passive and active attacks. Both in practice ( https://arxiv.org/pdf/1704.04299/) and just fundamentally: https://www.youtube.com/watch?v=9s3EbSKDA3o. There are ways to mitigate some of these problems to a degree. This is why you hear Monero people talk about coin control and churning (both of which can make you stand out in other ways). But the fact that they have to mention that should tell you its far from a perfect solution cryptographically.

There's a reason projects go with the large anonymity set approach. And if you're a cryptographer at ConsenSys, you should know that: it's what Ethereum is doing with Aztec. You also should know several projects, including Zcash, are working on trustless setup zk proofs.

(Disclosure: I am involved in Zcash.)