I have tried Vatican website to no avail.
Your trip isn't until April sometime, correct? They don't appear to be selling tickets or tours for 2024 dates yet, and I'm not all that surprised as the new measures don't go into effect until Jan 1. They're probably busy updating/overhauling the system.
You'll only be in Rome for two nights - which only gives you one full day - and I believe those two nights are a Sunday and Monday? As the museums are closed most Sundays, you must be looking at a Monday? I'd just keep checking the site to see when bookings becomes available for next year They may only sell general-entry tickets 60 days out (as has been standard) and tours or premium tickets further out than that, or none of the above but you should get a feel for when to be ready to spring before too long.
So, now we get regulation. And only the Vatican's preferred guides.
We don't know that yet. It could be that guides from the same companies already providing tours will still be allowed, just maybe not for as many tickets and not for early access. The ability of 3rd parties to obtain and sell general-entry tickets at inflated rates may also be history. It's a wait-and-see?