"convenient" heißt allerdings "praktisch, günstig, bequem"; da fehlt die Idee des "sorglos".

Bringt "all-in-one" wirklich die Idee des "rundum" rüber?

Übrigens, "all-round carefree package" bringt mit site:.uk ca. 870 Google-Treffer.

"convenient all-in-one package" erzielt mit site:.uk 589 Google-Treffer.

Not a small number of the "870 Google-Treffer" have non-UK sources.

"all-in-one assured package"?

If something is assured one doesn't have to worry about it - "sorglos"

assured:

Oxford:

"2[attributive]Protected against discontinuance or change.

Cambridge:

"assuredadjective (CERTAIN)

›certain to be achieved or obtained:

Now that the financing has been secured, the production of the film is assured.

Collins:

"2. adjective [v-link ADJ]

If something is assured, it is certain to happen. ⇒ Our victory is assured; nothing can stop us. ⇒ Yesterday, her future seemed assured.

3. graded adjective & adjectiveIf you are assured of something, you are certain to get it or achieve it. [+ of] ⇒ Laura Davies is assured of a place in Europe's team. ⇒ Bickerstaffe looks assured of being elected general secretary.

I suppose it will depend on the company’s tone and the key message, but it seems to be a nonsense to shoehorn "sorglos" into the English translation when "convenient" covers the idea that the person receiving the "package" doesn't have to worry about anything else. It's semantics.

We don't call slugs naked snails to convey the idea of nudity.

And Google hits certainly have their limitations when it comes to good style ... in a sentence I would favour something like "a convenient all-in-one package that offers peace of mind" – but this annoying compound noun often appears as an isolated text element on badly written advertising, defended by semi-literate copywriters.