Use of suffix 後 in place of a verb

Question

姉は大学を卒業後、家族から独立している。 (source)
My sister has been independent of the family since she graduated from university.

(the comma is my own, to break up that horrible string of kanji)

This sentence seems a bit weird to me because there is no verb to go with the を. If I'd written this I'd have gone with 大学を卒業してから (maybe having two からs close together is bad style?). Would this change the nuance?

How should I understand 大学を卒業後 grammatically? Is there a verb elided (I can't see what I could insert that would work)?

Is this structure common? Please could you give some more examples?

Answer 1

It is a bookish construction frequently seen in newspapers and academic papers.

You can simply understand it as a する omitted (with its tense).

大学を卒業[後]【ご】 → 大学を卒業した後【あと】
デパートで買い物[前]【まえ】 → デパートで買い物する前【まえ】
滑走路に進入[時]【じ】 → 滑走路に進入（する／した）時【とき】
ワクチンを接種直後 → ワクチンを接種した直後

These expressions can be used whenever the previous verb is a サ変複合動詞 (noun + する), but not for other simple verbs like 食べる, 話す etc.

I assume they are categorized as verbal adverbs or verbal adjectives grammatically, on the line of （携帯を～）充電中 and （現金に～）交換可能.