While I disagree with this statement, I don’t think satisfying the people in this thread should be the metric by which you decide whether to change the name or not. Given that the purpose of the trademark is to avoid consumer confusion, and given that, as far as I can tell, your product is the only product that has demonstrably been consistently confused with upstream nix, and directly competes with it, determinate nix is quite literally exactly what trademarks are built to protect against. As far as I know, you are the only commercial entity in such a situation. While certainly, the nix foundation does need a trademark on this, it still feels incredibly backhanded to name a competing product something similar enough to cause confusion, seemingly without approval from the nix foundation, when it’s clear that they should have the trademark, and the situation caused by the name is exactly what a trademark is supposed to protect against.
If you feel that this is wrong, you should probably change the name, regardless of whether you feel like it’ll satisfy the people in this comment thread or not. (That said, I do sympathize with the unfortunate situation that you probably would not want to name your product “dix”).
To the nix foundation, you should really talk to Determinate systems, and potentially send a cease and desist if necessary. I don’t mean to say that they are acting in bad faith, but the fact that this product exists with it’s name and function being so similar will weaken any attempts in protecting the future Nix trademark. I don’t think anyone here wants an actual bad actor to come in and try and take control over the nix name.