You could just wrap the web app in Capacitor for mobile and Electron for desktop, and easily use a SQLite db for unlimited persistence. If someone is interested in offline support, I don’t think it is a dealbreaker to have to download an app. That’s pretty common (eg Netflix, Spotify, hbo, any of the streaming services. The offline support only works in the app, not the web player).
Logically it's not a deal breaker (as Electron is quite mature) but practically there are a few problems:
Users are downloading apps less and less and relying more on web links from apps they already have.
So they mostly tend to end up on their browser anyway, and then workflow is disrupted while commuting and going in and out of signal.
Other less important reasons to consider would be in my opinion:
Electron is a bit too heavy on memory for users with 8GB and less of ram albeit it's gotten better lately.
I can't use ublock-origin on chrome or private-relay on safari while using an electron app (in this case however I still benefit from adding a blocklist like https://someonewhocares.org/hosts/ipv6zero/ to my /private/etc/hosts file on mac)
My experience is different regarding Electron apps. Many of the Electron apps I use (Spotify, Slack, Notion) have a web UI option. I never use it and now just a handful of people who sometimes open Notion or Slack on web.
