"deeply instructive" is a correct and usable phrase in written English.
You can use the phrase to describe something that is especially informative or helpful. For example, you could say, "This article was deeply instructive and gave me valuable insight into the issue."
It is a deeply instructive experience, a very interesting way to think.
All of which is to ignore the deeply instructive story of James Callaghan, Wilson's successor, on which I once, quite by chance, managed to eavesdrop myself.
Private Eye is, quite simply, as integral to British public life as the Times used to be – and this parallel is deeply instructive.
In the first episode, Menaker said that the "Bernie and Hillary divide is a profound and deeply instructive one — I can't see it going away".
But it was was deeply instructive, at the Fair, to meet Russian writers who have lived through the transition from an almighty state that bankrolled, overlooked and interfered in literature to a market-driven free-for-all.
The experience was profoundly instructive.
But it would be instructive and deeply pleasant work to compile a thick and ragged volume that might be titled "The Tao of Harrison".
Revisiting their original accounts and bringing their stories up to date proved an instructive and often deeply moving experience – and not just for me.
But, having said all of that, this was still an interesting and instructive poll, due to how deeply they examined the question of what the public would like to see done to fix the budget deficit.
Given Burt's influence, it would be instructive to know his sensibilities more deeply.
Given the stakes, the most surprising part of our perpetually dirty political system is that all the slings and arrows that once cut so deeply may later seem merely funny, or only instructive.
