I've just now gotten around to reading Deborah Harkness' Time's Convert (#1,008), the fourth book in her All Souls Trilogy. (See my posts of 4/1/2011, 7/31/2012 & 8/18/2014.) You may have caught the TV adaptation of these earlier books, called A Discovery of Witches on the AMC network.
Time's Convert doesn't focus strictly on Diana Bishop and Matthew Clairmont's story, but they are still major characters here, as the central figure is Marcus, a son of Matthew. He is about to mate with Phoebe, who has determined to become a vampire to match Marcus, but the protocols of the Congregation must be observed. Marcus is therefore banished for their waiting period to Les Revenants, home to Diana, Matthew, their twin toddlers and assorted friends and relatives. Marcus's restlessness leads him to confide in Diana about his making at the hands of Matthew at the time of the American Revolution, and his subsequent adventures as he grows into his role as a vampire and accomplished surgeon.
Again, Ms. Harkness' background as a historian shows up here with her factual references to little known aspects of colonial American history and culture. It's a fascinating read, but my complaint is still the same as it has been throughout this series - so many minor characters and referrals to events in earlier books make for confusing reading if you're not completely up to date with previous plots. I did recommend in post for The Book of Life that the reader might be best served by lining up all of books in the All Souls Trilogy and reading them back-to-back. The same is true with Time's Convert. I've enjoyed this series, but it does require some effort on the part of the reader. Maybe the pandemic is the perfect time to read them all!