It was to talk about "team restructuring"
where we required double digits of “nines” availability
Do you mean 99% or 99.99999999%? Because 99.99999999% is absurd. Even Google doesn't go near that for internal targets. That's 1/3 of a second per year of downtime. If a network hiccup causes 30s of downtime, you've blown through a century of error budget. If you're talking durability, that's another matter, but availability?
For ten-nines availability to make any sense, any dependent system would also have to have ten nines availability, and any calling system would have to have close to ten nines availability or it's not worth ten nines on the called system.
If the traffic ever goes over TCP/IP, not even if it ever goes over the public internet, if it ever goes over Ethernet wires, ten nines sounds like overkill. Maybe if it stays within a mainframe computer, but you'd have to carefully audit that mainframe to ensure that every component involved also has approx ten nines.
If you mean 2 nines availability, that's not high availability at all. That's nearly 4 days of downtime a year. That's enough that you don't necessarily need a standby system, you just need to be able to repair the main one within a few hours if it goes down.