It's not possible to synchronise filtering lists on the Apple Watch. The native Reminders app does this without any problems. Lists on the Apple Watch synchronise strangely with the watch, sometimes they do, sometimes they don't; I don't trust them. Adding tasks via Siri is very cumbersome. Overall, list synchronisation between devices is problematic; sometimes tasks added in the Eisenhower matrix don't appear in the matrix, magically landing somewhere else. Filtering lists are powerful, but they have quite a few limitations; they don't automatically add tags. On the Apple Watch, ticking off tasks involves significant lags, there are no animations, everything suddenly disappears, there's no undo option, everything is angular and unpolished, and that's where most tasks are added. Synchronisation between the watch and the phone is veeeery slow. It's a shame because cross-platform capability should be the hidden strength of this application. I recommend taking inspiration from simpler, less powerful applications that just do what they do well, like Reminders or Things 3.
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