Unless there's a client I can run locally, it's not decentralized in any meaningful way. Needs a link to the means I can sign up, login, and use this without relying on your web server at all.
The only part that isn't decentralized is the front end which is hosted on Netlify.
However, if you want to do everything without relying on me at all, you can also clone the repo and run it locally and everything should work the same: https://github.com/dkb868/socialvault
Nobody is going to clone the repo and run it locally. Anyone willing and able to do that has no need for this tool. You've gotta pack this thing up and make it like a regular application, or at least a browser plugin. No localhost web servers or anything like that. It has to look like a trustworthy and professional app like Slack, Dropbox, or Lastpass.
I'm not sure mass appeal matters much here anyway. I could get behind the "sell yourself better" comment but this is such a niche application I'm not sure packaging it more neatly would net appreciably more users running it locally.