Hi Miriam,
Thank you so much for taking time to answer this. 
So far, officially Google Jobs is not working in Ireland, but in fact we see these results for almost all best keywords.
https://drive.google.com/file/d/1hqi8nt2A_up9R0UZgxyjq-VXjg3O7HRl/view
https://drive.google.com/file/d/1OFH-qreM4lKlfJ_-RLYBNh1Kcw_j8k1Y/view
Big jobs companies, pull jobs data and publish it "mediated" by them.
Therefore, my client's website from rank an average of #9 two months ago, now it has an average of #11.
That is one result. Of course, the big companies publish the jobs, which are published first in my client's website. Those companies do not offer a link to my client's website, instead the URL without a link, the same with the contact email.
Truly, I can advise him to improve the structured data for jobs, but with those overwhelming DAs, I am not sure if it might work at all.
I am fully aware that it is imposible to compete with companies with over 100,000 back-links, despite my client has a 21 years old recruiter company with great reputation.
Any ideas?
Thanks in advance for any help and/or thinking about the issue.