I'm not making an argument when asking you to compare signature schemes (you brought up something irrelevant and I clarified for you that it would go nowhere, you're welcome). I was being helpful to help you get your terminology straight.

People who don't run nodes cant be 100% sure the Bitcoin they hold is real or have the unencumbered ability to broadcast transactions to the rest of the network. People who don't run nodes aren't actually using Bitcoin to its fullest extent, even if they hold their own keys. It's not ideology, it's just the way things are, a necessity. No permission necessary. It's a learning process everyone goes through, and not going anywhere.

Payjoin is not privacy by obfuscation, obfuscation would be sending Bitcoin in random amounts over and over again to yourself as privacy measure (this doesn't work because of input heuristics). Payjoin is a protocol to construct bitcoin transactions.

Payjoin allows users to break input heuristics by allowing users to coordinate how to use inputs from multiple parties in transactions, securely. (I brought it up because it uses the similar ECDH signature schemes "from the 70s-90s" you listed). Does it solve "privacy"? of course not (theres other heuristics), but it's an incremental improvement addressing a need; another option to construct transactions which wasn't available before.

Privacy means a lot of things. What I think you possibly are trying to get at is the transparency of all transction that happen on Bitcoin being out in the open makes for bad privacy. That's just the nature of the design and has little to do with signature schemes or hashing algorithms. Privacy isn't a feature of the base layer (utxos), and the idea is to build privacy tools in protocols using the existing utxo set instead of going out and build a whole new token. Amounts of all utxos are out in the open in order for anyone to independently validate that supply and issuance schedule are being followed and not being changed without anyone knowing.

Personally "Use this token if you want privacy" doesn't make sense to me. Cryptonote tokens don't have the same assurances.

Speaking of obfuscation, perhaps that applies to RandomX alongside countless other memory intensive PoW schemes. The claims you made that those PoW schemes have advantages in accessibility, ubiquity, plausible deniability (strange selection btw) and declaring those schemes as means to control energy draw, noise, or heat is nonsense. Those schemes exist to obfuscate energy use -- adding unnecessary complexity to a transparent process.

PoW is about energy placing a physical constraint on changing something in the digital space. Being able to channel as much energy as efficiently as possible is exactly how people came to iterating ASICs, and if you are at all worried that the developments in that space could "break" Bitcoin, its already been solved for you with the difficulty adjustment. (the only thing as scarce as block space on this planet, is wafer space)

Almost any device can be used to construct SHA256 hashes (you can even do it with pen and paper), ubiquitous and accessible which is why hashing can be performed anywhere by anyone -- starting with a humble single CPU. It's an even playing field. There's really nothing stopping you from buying top-of-the-line chips on your own and assembling your own device to fit your power envelope or trying your luck on your laptop. Someone recently found a block solo-mining with a BitAxe using like 5 BM1366 chips (~80 Watts of mining power) -- for reference an S21pro has 432 chips (3500 Watts).

I suppose there's not much point comparing Bitcoin and what remains of cryptonote tokens. I will admit I don't have the mental bandwidth to keep track of anything outside of Bitcoin. It may seem like your token is still ticking along, but it doesn't to me.

Happy to be proven wrong, don't let me stop you from holding more tokens