Hi, David. Thanks for your detailed question.
These tags are actually shared from your Posts tags; they’re not specific to Events.
Therefore, the tags archive page (like the one you linked to) is your theme’s normal tag archive page.
Are you experiencing the same order of posts (by date published?) at all your tag archives (of the tags without any events in them)?
I’ve never used it or heard of it before, but https://wordpress.org/plugins/chronological-posts/ (third-party, not guaranteed or supported by us) or something like it might come in handy.
And trying out some URL query arguments and these other tips might be helpful too.
Please let me know what you find out.
Thanks.