The build process is very fragile for both Android and iOS. Basically, a patch version update of any of the capacitor libs or plugins has a pretty high chance of wrecking your build pipeline.

Also the ecosystem is not in the best shape; the quality of libraries is allover the place, lots of unmaintained ones or ones that only support older SDK versions of Android/iOS. Not sure it's entirely fair to blame CapacitorJS for this, but it's nonetheless the reality when developing Capacitor applications.

All-in-all Capacitor is pretty great though, definitely one of the most productive ways to develop high quality cross-mobile apps.