High speed, zero stop trains? (Frecciarossa)

Is there any rhyme or reason to when these tickets are released? (High speed train, Frecciarossa)

I've seen some posts answered in this sub about how they hold tickets until anywhere from 90-180 days before travel date.

We're going to be traveling from Milan - Venice - Florence - Rome all by train and would much rather pay the money to save the time, but we cannot find the availability.

Do these sell out immediately for late August? I understand it's the busy season so it wouldn't surprise me.

Or do I just keep waiting? What's your method of keeping an eye on these? Any notifications to set?