Hello Mr. Cloudflare,
Your whole understanding of how XMR works seems to be wrong; theres no concept of spend outputs at all, to deanonymize tx with a certain certainity one would have to own around 83% of the networks outputs.
Optional privacy a la ZCASH is broken by design and cannot work, you are still able to have tainted coins and do blacklisting etc, its effectily useless, also it opens up a whole world of other attack vectors like this one: https://github.com/zcash/zcash/issues/1360#issuecomment-2461...
- multisig with zaddresses seems not to be possible. - Using Z Addresses on a Smartphone or HW device like Trezor is too resource intensive
Looks like a privacy disaster to me, as no one will be using it.