The root of the issue seems to be the longstanding deficiency that Texas either cannot or does not localize their emergency alerts at all.
I've lived in 2 other decently large states including California and left Amber Alerts enabled because they were infrequent and caused me no trouble - and they were infrequent because you only got alerts for your immediate area. As soon as I moved to Texas I had to disable them because they're all statewide, so your phone just gets blown up with them if you disable them.
Alerting a 5 mile radius about a killer on the loose is reasonable. A 600+ mile radius is not.