For a side note, from technical perspective, there is no differentiation based on where you are located and which timezone you are in.
Which email provider that you use may matter, but it only matter whether it goes to spam or inbox.
This is based on the assumption that IRCC does not do any trick on their email distribution system filtering and sending emails per location etc, and it is unless otherwise they have multiple systems all over the places to send batches of emails separately (which I doubt).
The batch system will fetch email address and send email. Simple as it is.
For 100,000 emails, it is a lot, but if you think about it, it is really not that much to take up to few days to completely send all emails unless otherwise they do it manually.
There is no point of asking where, or which emails you are using.
From what we observe, they sent out the batch email around 7~8AM PST, and not heard any further emails. And no rejection email in that batches.
Let's figures crossed, and wait until we hear something new.