I created a member list for people that logged in after 01/01/2020 in the cp.
You could send a email from that.
It is not that large
Just one page
Just select the saved search login after 01/01/2020 scroll to the bottom select email for action.
Then all from search.
On the next screen add your content and send
There is also a test email in that page where you can send just one email to yourself for a test.
I am trying to remember the limit from the host but I am thinking 30 per hour so You need to keep your browser on that page for the duration.
You can still open another browser window to visit the site.
