It's no issue if I were to attach it to to the acronym directly, but if I were to introduce an acronym for the first time in my writing I would have to use the full name with the acronym first, and that's where I'm stumped.
E.g. SWOT's (Strengths, Weakness, Opportunities, Threats) usefulness is debatable.
OR
SWOT (Strengths, Weakness, Opportunities, Threats)'s usefulness is debatable.
Which?
A common solution is to avoid making the acronym a possessive entirely through rephrasing:
The usefulness of SWOT (Strengths, Weaknesses, Opportunities, Threats) is debatable.
A Chicago Manual of Style blogger recommends that change:
Q. When we first use an acronym or initialism like FMCSA we put it in parentheses after the spelled-out version. If the spelled-out version is possessive, does the acronym/initialism need to be possessive too? Example: the Federal Motor Carrier Safety Administration’s (FMCSA’s) new rule or the Federal Motor Carrier Safety Administration’s (FMCSA) new rule?
A. This question is surely one of the most frequently asked; in the next edition I hope we will issue an explicit ban on this construction. In the meantime, please reword the sentence to avoid the possessive: the new rule issued by the Federal Motor Carrier Safety Administration (FMCSA).
The combination of characters )'s is not correct English. An apostrophe after a closed parenthesis doesn't have any meaning. So that option is out.
The other option is better, however, this issue shouldn't really ever come up, for the reason that you've parenthesized the wrong part of that sentence.
As explained in this answer, "Which would you place in parentheses: the expansion or the abbreviation?", the parenteses go around the abbreviation, not the spelled-out version. In other words, it should be, "Strengths-Weaknesses-Opportunities-Threats's (SWOT) usefulness is debatable."
If that still doesn't suffice, rephrase: "The usefulness of the Strengths-Weaknesses-Opportunites-Threats assessment (SWOT) is debatable."
