If you can’t find a name that you think “that’s the one” by the registration deadline (often tends to be a name you can’t let go of and would be gutted if someone close to you used?) - then imo you just do your best for your DC by giving them a “classic” name (usually something that has either been in the Top 100 for yonks or one that rarely has, yet still feels well known and like it could suit any age woman).
The benefits of “classic” names are that generally people can easily pronounce them, hopefully spell them and likely it won’t be quite as easy to give away DD’s age, social background etc as the names often aren’t as trendy and have had plenty of historical use. Preferably one with at least a couple of nickname choices in case DC (or yourselves in a month or two) prefer the sound of something slightly different. Classic name lists are always huge but something like:
Eleanor (Nell, Leni, Ella, Ellie, Nora)
Helena (as above without Nora)
Elizabeth (too many to list)
Julia/Juliet (Jules, Lia/Letty)
Josephine (Jo, Josie, Effie, Sephie, Gigi)
Emily/Emilia (Emmy, Milly, Mila)
Antonia (Anya, Annie,Toni, Nia, Nina)
Annabel (Anna, Annie, Belle, Bella)
Susanna (Suki, Susie, Sunny, Annie)
Louisa (Lou, Lulu, Lola)
Isabel/Isabella (Izzy, Bel, Bella)
Claudia (Claud, Cadi, Kit)
Imogen (Immy, Ginny)
Charlotte (Lottie, Charlie, Carly)
Caroline (Carrie, Callie, Caro)