I’ve just posted a dedicated topic for this deprecation, and I’ll update the warning banner to link there instead of taking people directly to Ember’s docs.
To expand on this: disabling them will remove the error banner, so that’s fine if you really need to hide it.
But it’s worth noting that deprecation notices don’t mean something is broken. It means that it will be broken in future, and we’re giving developers some advanced warning of that. It’s fine to keep using these things in the meantime.
On the <script> tag deprecation, we have a timeline here - everything will keep working until September.