Given that: a preposition or conjunction
The Oxford Living Dictionaries defines given that as a conjunction.
when you consider something
However the dictionary defines the preposition given in the following way:
taking into consideration.
Example:
It was surprising the government was re-elected, given that they had raised taxes so much.
However, the examples of 'given' as a preposition contains the same phrase 'given that' as the example of conjunction mentioned above do:
‘Physically shutting down the site would be very difficult given that it is hosted overseas.’
‘His achievement is all the more impressive given that Fitzgerald has endured his fair share of injuries.’
The Oxford English Dictionaries also gave the examples of 'given' as a preposition without adding 'that' following by it:
‘I pointed out that this might prove to be rather ironic given the current circumstances.’
‘The authorities appear to have succeeded in this given the enthusiastic response.’
I need someone's guide to guide me pertaining to their syntactical and phrasal similarity/differences.
There are many ways in which one can apply parts of speech. Different systems exist with different definitions for each part of speech. But let's use the system your sources are suggesting.
Given can be analysed as a preposition. But, when you add the conjunction that, the whole (given that) turns into a conjunction-like phrase.
Compare this with in:
I live in a house. (a preposition)
I live in the house in which I was born. (a conjunction-like phrase, if we follow the conceptions from system above)
Adding that or which (conjunctions / relative pronouns) can turn a preposition into a conjunction-like phrase. This can be seen in the fact that what follows that/which is a full subordinate clause, with a finite verb of its own (was (born)).
The authorities appear to have succeeded in this given the enthusiastic response. (a preposition)
The authorities appear to have succeeded in this given that the response was enthusiastic. (a conjunction-like phrase followed by a full subordinate clause with finite verb)