Is maintaining the Elixir backend your only problem? Is there any other issues related to Elixir that made you regret your decision? Because if there isn’t, then whatever backend you decide to have you will have to maintain it. Unless you can go full Firebase but that comes with its own limitations.
Also, if web is involved, Flutter Web is a bad, bad framework. For MVP you could maybe stick to familiar tech stack and do something like OnsenUI or Ionic, and then move to more native solution when you have some dedicated availability? I haven’t been on this space since 2017 but those were good enough back then.
Edit: I wouldn’t bet on LiveView for mobile apps just yet. You need to keep your options open and having an API is optimal for that. You can wrap a web view or move to native and even switch from flutter to compose etc if you have this option. With LiveView you might have to touch some backend code again to switch front end to native if (and with mobile, it’s more of a when than an if) needed.
