As I noted, you may doubt that a job opportunity in the U.S. is not a reason for urgent processing, but again that it is NOT a reason is about as close to certain as it gets.
My sense is you fail to recognize what is meant by "need Canadian citizenship" for the employment, perhaps looking at this from your personal perspective (as in what YOU need) rather than when Canadian citizenship is a legitimate qualification for the job.
If an individual can qualify for the job without Canadian citizenship that means Canadian citizenship is not a requirement for the job. So, for example, if a person can qualify for the job if they have U.S. citizenship, that means Canadian citizenship is NOT needed.
It would be a rather unusual circumstance for a U.S. job to not be available to a U.S. citizen who otherwise qualifies for the job.
The fact that you personally could qualify for the job if you have Canadian citizenship, and you cannot otherwise because you do not have other status which would make you qualified, does not make Canadian citizenship a legitimate qualification for the job.
The other aspect of this many seem to not grasp is that a job requirement based on having a Canadian passport, usually related to the job's expected travel requirements, is similarly NOT a job for which Canadian citizenship is needed. Sure, Canadian citizenship will allow the individual to obtain a Canadian passport, and that may meet an employer's requirements, BUT that is NOT ORDINARILY considered a reason for urgent processing.
Moreover, there generally needs to be a legitimate, genuine connection between citizenship and qualifications for the job . . . and this is typically about certain Canadian government jobs or jobs with Canadian government contractors, and mostly (albeit not entirely) due to security related aspects of the employment.
As I have oft said, USUALLY there is no downside to asking for urgent processing. And IRCC can be a lot more accommodating, SOMETIMES (not always, maybe not often, but sometimes), than many anticipate. IRCC has the discretion to expedite any applicant's case. So sure, one can ask, and sure there is a chance to get urgent processing.
BUT proffering a job opportunity in the U.S. probably NOT a good idea:
Proffering a job opportunity in the U.S., however, might be considered a risk indicator triggering elevated scrutiny, resulting in long delays in processing rather than routine let alone expedited processing. Historically it has appeared much of the fraud in citizenship applications is related to obtaining Canadian citizenship as a stepping-stone to work in the U.S. Thus, for a long time, appearing to apply-on-the-way-to-the-airport has been a factor increasing the risk of elevated scrutiny, including RQ (the Liberal government, before the Harper government, for sure introduced a risk indicator related to this at least as far back as 2005 in an OB which was added as an appendix to the Operational Manual governing residency until replaced by PDIs under the Harper government).
Until the current Liberal government repealed it, the Harper government had focused so intently on this that it effectively made applying-on-the-way-to-the-airport a ground for rejecting an application, by imposing an intent-to-reside requirement. The repeal of the intent-to-reside requirement does not mean appearing to apply-on-the-way-to-the-airport no longer increases the risk of elevated scrutiny. The historical association of such applicants with instances of fraud remains what it is, meaning a reason to at least check out such applicants more thoroughly to make sure they are not involved in a fraud. That can mean non-routine processing, meaning delays, sometimes long delays. Not the sort of risk someone who wants urgent processing would be prudent to take.