Start with high-confidence renaissance ya books, then narrow by subgenre or adjacent topics.
Da Vinci's Tiger
L. M. Elliott
The Smile
Charlotte Miller, Donna Jo Napoli
Doomed Queen Anne
Carolyn Meyer
Patience, Princess Catherine
Daughters of Rome
Kate Quinn
Prince of Shadows
Rachel Caine, Kyle McCarley
The Wild Queen
The Bad Queen
Everything Is Poison
Joy McCullough
The Vanishing Point
Louise Hawes
Queen's Own Fool
Jane Yolen, Robert Harris
The Other Boleyn Girl
Vanessa Kirby, Philippa Gregory
Medici Heist
Sara Alexander, Caitlin Schneiderhan
Maria and the Plague
Natasha Bacchus-Buschkiel, Francesca Ficorilli