Is there a word for congruence between a software platforms' purpose/structure and the actual experience of using it?

One thing fully coheres with another. The purpose of this software coheres with user experience.

("Congruent" does fit as does "coherent")

In your context:

"Mimetic" means that a thing mimics another thing.

"Complient" means a thing that fits the requirements of another.

"Harmonious" means a thing works beautifully with another thing.

I'd suggest dropping "is fully" and replacing with "mimics", "matches" , or "copies", though. That is shorter and probably says the same thing you intend.

"... fully aligned ... "

Although "coheres" is glorious!

You could say that they are in tune with each other:

in a state in which one thing agrees with or matches another —usually + with • His formal clothing was in tune with the occasion.
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This can also be stated as "in harmony".

For your sample, the first word that came to my mind was integrated:

With various parts or aspects linked or coordinated.
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It works nicely in your sample:

Our SaaS platform's deeper learning workflow is fully integrated with the actual process of using deeper learning for professional growth.

However, if you want a word more focused on the experience of the participant, you can borrow from virtual reality terminology: immersive:

seeming to surround the audience, player, etc. so that they feel completely involved in something:
• an immersive theatrical experience
• The new game is more immersive.
Cambridge Dictionary

Unfortunately, using immersive directly in your example is a bit awkward, so I have reworded it slightly:

Our SaaS platform's deeper learning workflow is fully immersive, enabling the actual process of using deeper learning for professional growth.

But if the exact wording is important, you could used immersed:

Our SaaS platform's deeper learning workflow is fully immersed with the actual process of using deeper learning for professional growth.

You can say that they are correspondent:

1: having a relation of likeness : being similar or analogous to something

2: being in agreement : suiting, fitting — used with with or to

So your sentence becomes:

Our SaaS platform's deeper learning workflow is fully correspondent with the actual process of using deeper learning for professional growth.