If I need to participate in on-call rotation or similar, I expect the employer to issue a phone. For a remote job, I will obviously get one myself -- but then strictly for job-related activities.
(by the way, if anyone is looking for an experienced infrastructure engineer/"DevOps" guy, give me a cal...errh email)
You probably don’t realize nor intend this, but that can be a large red flag for your candidacy from the other side of the table, particularly if the role involves security because you’re broadcasting a slight misjudgment of your threat vectors and exposure. The number of resumes most folks go through, expecting ravens from Winterfell will get you dropped fast. Torvalds could probably get away with making initial hailing frequencies that difficult, but you or I should just buy a phone number of some kind, as much as it sucks.
The phone isn’t the problem if you apply opsec correctly, buy the right one, and operate it like a compromise hazard. (It is.)
Anyway, point is, if you need a temporary phone while job hunting, try google voice? I hate google now but this may help temporarily, or maybe you could find a better provider (other than google, that is).
Good luck with the job hunt!