This is an open question to the community, do you see any value in having a fully decentralized non-custodial BTC mixer? I am currently building a centralized solution with some unique features, but I got some ideas for how to make a decentralized one work and am trying to decide if it's worth the hassle to work on it.
In V1 (centralized) that will be launched in the following days users will have the option to choose from 2 mixing methods. The 'fast' one, which is similar to the other solutions available (you deposit and select how many withdrawal addresses/amounts/elapsed time you prefer and done you will receive your funds according to the schedule you set), or the 'slow' one, which works in a similar way to Tornado Cash if any of you are familiar with that. How it works is a user would go on the platform and generate a "Note", afterwards he deposits funds into the specified address and they get credited to his "Note". Then he can withdraw any amount from it at any point in time. So for example you could withdraw 20% of the balance after 2 days, another 30% after 1 week and the rest after 1 month, thus making it close to impossible to track movement of funds. And with more time passing and more BTC/deposits/withdrawals are performed the anonimity gets stronger and stronger. PERFECT privacy for Bitcoin doesen't exist, but I believe this model is as close as you can get to it. If you use it the correct way there is no possible way to prove your funds are coming from a specific address unlike some other solutions where it may be harder to do but nonetheless feasible.
In the possible V2 I am envisioning the process would stay pretty much the same except for the fact that anyone will be able to become a "validator" and so the protocol will become fully decentralized, meaning that it cannot be changed or tampered with by anyone - not even the original developers.
Without a doubt there's huge demand for a non-custodial mixer - trusting the centralized party is and always will be the largest weakness of any mixer. The catch is that it's unfortunately often difficult to build a decentralized product and keep it properly funded. Your model sounds relatively similar to Chipmixer, which in my opinion, has an edge over most other mixers in the strength of their privacy since you can spend the chips whenever you want, like the Notes in your model. As far as I know, there's no decentralized 'version' of Chipmixer though.
While the true innovation is in a decentralized model, I also have to say that I really like your idea of starting with a centralized model first. I've been working in the crypto space for a few years on various projects, and there was a huge push for decentralized products (like DEXes) back in 2019 or so. My thinking and arguments were always that we needed to continue building our centralized product and getting it stable first,
before focusing on the decentralized product. It's just business reality that you need to get your funds and structure stabilized in order to have the runway and foundation to build the decentralized product. I butted heads quite a lot on that back then, although I think history has shown that the centralized companies have had more success. It gets a lot of hate, but that's just the reality. I'll be following along, it sounds like you've done a crypto venture or two before, and I'm looking forward to seeing and hopefully helping to alpha or beta test it when you launch it.