After literally decades of using Microsoft Word I just found out that it does regex!
I discovered this because I needed to delete comments inserted throughout my book manuscript, in the form
For example, to get rid of the pesky markup in my manuscript, I just had to tell the Replace dialogue to use wildcards, and then had it search for \<AU:?\>. The backslashes are necessary so that the angle brackets are not read as regex instructions. The question mark tells Word to find everything between <AU: and >. Simple! And it accepts far more complex regular expressions that. (Here’s a site that lets you test your regular expressions.)
Take a well deserved bow, Microsoft Word! (And then fix auto-numbers.)