How to Constructively Deal with Email Invitations to Scam Conferences or Journals? Today I received the following email which was entitled the same as one of my publications:

Dear Dr. Ian,
I followed your research works which were of extremely high standard. I would like to invite you to the World Pediatrics Webinar 2021 which aims to accelerate scientific discoveries and major milestones in the field of Pediatrics. The conference will be held during June 08-09, 2021.
Conference Website: https://www.▮▮▮▮▮▮▮▮-▮▮▮▮▮▮▮.com/
You can directly contact me through Whatsapp: +37▮▮▮▮▮▮▮▮▮
Please let me know your interest so that we can discuss further. Looking forward to hearing from you soon.
Sincerely,
Ian Watson | Program Manger
World Pediatrics Webinar 2021

I get a few of these scam conference or predatory journal emails a week. It takes about 500 milliseconds to recognize the scam. First, that paper was not of extremely high standard. Second, Whatsapp, really? I dutifully report them as junk to my organization's email platform, but they keep coming.
I've found a couple of tangentially related questions:

How to warn others about a conference-related scam?
How to make sure that a conference is not a scam when you are invited as a speaker?

The first has to do with a specific scam associated with a particular conference and the second is about identifying the scam.
In contrast, my question is about how to deal with the problem once identified, productively.

What arguments can I make to my academic institution's IT department that blocking these emails should be a priority?
If I can't convince my IT department to block the emails for everyone, is there an authority I can complain to? Google? The website's hosting provider? The payment processor?

In addition to the annoyance (which spread over an organization sized number of individuals is considerable and detracts from meaningful academic pursuits), academics fall for prey to deceptive practices all the time [1] [2]. This means potentially hundreds  wasted on registration fees, which are frequently paid by funds provided by taxpayers or charitable organizations.
I am going to focus on your point 1:

What arguments can I make to my academic institution's IT department that blocking these emails should be a priority?

Please don't.
If you manage to convince your IT department to make it a priority to block such emails, then it's quite likely that there will be false positives across your institute. You say that it is straightforward to identify these scam emails, and I have no doubt that as a human, indeed, you can. But there will also be humans writing invite emails on behalf of legit conferences or journals. Those humans may not have English as their first language. They may inadvertently use turns of phrase that you find characteristic of spam invites. As a consequence, some legit invites will be discarded along with the spam invites. The cost of these discards is asymmetrical: the cost of manually discarding spam is a slight annoyance, but the cost of having a legit invite discarded could be a missed career opportunity.
Ask yourself: how many colleagues missing out on legit invitations is it worth for you to no longer have to manually discard the spam invitations?