I don't think time spent is a good metric when one game runs smoothly and seamlessly and is active gameplay the whole way through... and the other has you doing 20 minutes of inventory management and fighting with the UI for every hour of engaged gameplay.
BG3 up to the newest content (not including grymforge was of the latest patch, as I've not done the metric on that yet) has ~50 combat or combat-like encounters, each of which more or less always play out the same way, and each of which, once done, are done and offer nothing further. No, that's not, in my opinion, "more content than most fully released games"
