Back when I was doing academic publishing I'd use a regex to find all the hyperlinks, then a script (written by a co-worker, thanks again Dan!) to determine if they were working or no.
A similar approach should work w/ a DOI.
A similar approach should work w/ a DOI.
I work on Veracity https://groundedai.company/veracity/ which does citation checking for academic publishers. I see stuff like this all the time in paper submissions. Publishers are inundated