This is the last time that I am replying to AI slop.
The case in 2019 was not a failure of the protocol nor the security, you can use your brain to read and educate yourself:
https://web.getmonero.org/2018/09/25/a-post-mortum-of-the…
The second case involved a modified wallet library and mining exchanges to publicize transaction receipts and even this only gave a low probability of being detected. Normal users don't publish their receipts nor use modified wallets. In either case, ring size was increased, zero transactions were ever compromised.
You can read this by yourself:
https://arxiv.org/pdf/2408.05332
Instead of using AI slop. As mentioned, I won't reply again to bots with low-quality information