Are "consider" and "take into account" always interchangeable?
Your point is well illustrated by the Cambridge dictionary . Others are similar.
to take into account = to consider or remember something when judging a situation
Cambridge dictionary
consider = spend time thinking about possibility or making decision; think carefully about something
Cambridge dictionary
But there are hints of difference. Merriam Webster does not give consider as a synonym for take into account:
Synonyms & Antonyms of take into account: to give consideration to (as unexpected circumstances or contingencies)
Taking into account the possibility of stormy weather, we decided to spring for a cabin instead of pitching a tent.
Synonyms for take into account: allow (for), consider, factor (in or into), provide (for), regard.
Words Related to take into account: accommodate, adapt, adjust, condition, anticipate, contemplate, envisage, expect, foresee, assume, presume, presuppose, plan
I suggest that small differences exist that depend on the use of account. As a financial analogy, taking something into account is to enter it into the account along with other items, where it inevitably will determine something of the final outcome. To take something into the account of a series of events inserts it in the record of events. To take account of points of argument is to use them to resolve the final conclusion.
To take into account is therefore sometimes different from mere consideration, which may have no influence on the final outcome or on the record. For example, when writing an article about meteorological phenomena on a rotating spherical earth, I may consider others' assertions that the the earth is flat, but I reject them and my article does not take them into account. (Note that my article is not about the flat earth controversy itself; it is about weather systems on a rotating sphere.)
On the other hand, if the weather forecast is poor, I not only consider it but I act on it by taking it into account when planning my voyage.