Det dynamiske flyttet er vanskelig.

Yes—this is a normal Norwegian pattern often called double definiteness.

When a noun is definite and also has an adjective before it, Norwegian usually marks definiteness in two places:

• with a separate article: det
• with the definite ending on the noun: -et

So:

• et flytt = a move
• flyttet = the move
• det dynamiske flyttet = the dynamic move

So det here is not the English pronoun it. It is part of the definite noun phrase.

Because flytt is a neuter noun.

In Norwegian:

• den is used with common-gender nouns
• det is used with neuter nouns

Since the basic form is et flytt, the definite phrase uses det:

• et flytt
• det dynamiske flyttet

If the noun were common gender, you would use den instead.

They are in different positions and follow different rules.

• dynamiske is an adjective before the noun (attributive adjective)
• vanskelig is an adjective after er (predicative adjective)

In det dynamiske flyttet, the noun phrase is definite, so the adjective before the noun normally takes -e:

• det dynamiske flyttet

After er, the adjective is predicative:

• flyttet er vanskelig

Also, vanskelig is one of many adjectives ending in -ig that usually do not add -t in the neuter singular. So the form stays vanskelig.

Compare:

• et vanskelig spørsmål
• spørsmålet er vanskelig

Here it is a noun.

The basic noun is flytt, and flyttet is its definite singular form.

So in this sentence:

• det dynamiske flyttet = the dynamic move

It can look confusing because flyttet can also be a verb form in other sentences, for example:

• Han flyttet i går. = He moved yesterday.

But in your sentence, because it comes after det dynamiske, it is clearly being used as a noun.

The structure is:

• Det dynamiske flyttet = subject
• er = verb
• vanskelig = predicate adjective

So the sentence follows a very familiar pattern:

subject + is + adjective

That is one reason this sentence feels quite straightforward to English speakers once the noun phrase is understood.

Yes. If you wanted to say a dynamic move is difficult, you would use:

Et dynamisk flytt er vanskelig.

Notice the changes:

• det disappears, because the phrase is no longer definite
• the noun becomes flytt instead of flyttet
• the adjective becomes dynamisk instead of dynamiske

So:

• et dynamisk flytt = a dynamic move
• det dynamiske flyttet = the dynamic move

It is grammatically fine.

However, whether it sounds fully natural depends on what flytt is supposed to mean in context.

• If you mean a specific move or relocation, flytt can work.
• If you mean the general process of moving, Norwegian often prefers flytting.

So in some contexts, a Norwegian speaker might more naturally say something like:

• Den dynamiske flyttingen er vanskelig.

But as a grammar example, Det dynamiske flyttet er vanskelig. is useful and correct.