All of their transactions are visible in the ledger, not hard to find. The same tools they used still exist today, except with additional privacy enhancements like some chains using zk-SNARKs.

The only weak points are exchanges. The OP can decide how anonymous they want to be - complete anonymity would imply not exchanging to fiat at all.

The weak points are literally anything beyond transfers between clean accounts. Want to buy anything? It needs to be picked up. Want to transfer money to someone? They can be asked about you. Want to pay for services? You need to access them in a safe way. Even submitting new transactions, you could be traced by enough nodes if someone actually cared.

I don't disagree that most of them are not practical for a rando developer who wants to be anonymous, but I'm still annoyed at "the only weak point is...".

If you are an anon dev and you share your real identity with a counterparty, you aren’t doing a great job at staying anonymous.

Anybody can start a new crypto wallet and receive funds into it, and then make transactions and keep that value on-chain to remain anonymous. There are a number of anon devs in the Ethereum ecosystem doing just this.

With enough effort your IP might be traceable if you do something like mint a token from a compromised website. But advanced methods also exist to break anonymity in systems like Tor, VPNs and cash which we often consider to have strong properties of privacy and anonymity, and to this nobody would refute as “bullshit.”