vfinn, editing my last post as there is indeed a brand-new 3-day combo pass! They must have added this very recently, and it was hiding on this page....
https://operaduomofirenze.skiperformance.com/en/store#/en/buy
... down in the dark blue box at the bottom of the page, and in the menu right under the pix of the painting. Clicking "Tickets from March 1, 2022" brings up the page with that option, although it doesn't seem to have a separate URL I can include a link to (or not yet, anyway).
This is GREAT; glad to see that they've brought this option back, and thanks for bringing it up!
There is more info on these passes on the FAQ page:
https://operaduomofirenze.skiperformance.com/en/store#/en/support/faq
Lifting this text from the "NEW TICKETS FROM 1ST MARCH 2022. HOW DO THEY WORK?" section, it does appear like you have to book your dome climb slot for the first day of the 3-day pass validity.
"... it is valid for 3 calendar days from the date of the visit booked during the purchase phase (eg. I purchase the climb to the Dome for 1 January at 11:15 am, the ticket will be valid on 1, 2, 3 January)".
Clear as mud? 😉
Additionally, there are two other combo passes available on that page, one with everything but the dome climb (Giotto Pass), and one without the dome and the belltower (Ghiberti Pass). Lulu, take a look????