I can’t say these adapters break easily. We are using many FF800s here in a shared user environment over many years. I had more failures of FireWire cables over the years than those adapters.

Also never had a problem with daisy chaining, but make sure to connect to the Mac to the FireWire 800 port (not to the 400 port).

I have been using this connection with the original Apple adapters for many years now (+6 years?). They are still the first and only set of adapters and have never been changed. No problems and instabilities at all over the years and still now.

More power to you, thats great, let's hope they last for long.

… To your question if it is stable, no, it is not stable because these adapters you have to use for firewire connection, are prone to burn out at long time usage, these Apple adapters are expensive sold but very cheap made. Not reliable, not stable.

I have been using this connection with the original Apple adapters for many years now (+6 years?). They are still the first and only set of adapters and have never been changed. No problems and instabilities at all over the years and still now.

You have to stay on an old MacOS not allowed to upgrade to MacOS Tahoe with the FF800 in use.

My recommendation, get rid of the FF800s and upgrade the computer to the latest OS.
For 32 analog inputs and outputs, cheap solution : RME Digiface USB plus 4 x Behringer ADA8200 = ca 1060 Euro

More I/Os, more expensive : RME UFX lll plus some converters from RME or Ferrofish

To your question if it is stable, no, it is not stable because these adapters you have to use for firewire connection, are prone to burn out at long time usage, these Apple adapters are expensive sold but very cheap made. Not reliable, not stable.

Welcome to the RME user forum.

I am not using Mac. But as far as I understood, there are two connection methods possible:
Daisy Chaining and Aggregate Devices.

While FireWire allows physical daisy-chaining, on Apple Silicon with adapters, the Mac will see them as two distinct CoreAudio devices. To use them together, you would have to create an Aggregate Device in macOS Audio MIDI Setup.
I read that this is historically notoriously unstable with FireWire-to-Thunderbolt adapter chains.

Both methods have one drawback: you need to route through the DAW with higher latency,
depending on buffer settings, when routing audio from an input of FF800#1 to an output of FF800#2.

Depending on your use cases, direct routing on one interface is preferable.
E.g., if a vocalist sings to a backing track for latency-free monitoring through headphones.

3rd possibility: the ADAT Expansion Method (best current solution instead of daisy chaining or aggregate device)
You could achieve this by using one FF800 as the main interface and connecting the 2nd FF800 through ADAT.
Either in stand-alone mode or connected through FireWire to be able to operate it.
By this you can perform latency-free direct routing without having to route through FireWire or the DAW.

BTW, I read that FireWire support has been ceased by Apple in the latest versions of macOS.

4th possibility - upgrading the main interface (the best long-term solution):
Get one USB or PCIe-based recording interface with the needed port capacity
and connect preamps and/or AD/DA converters to it.

Anyone tried to add a second FF 800 to get more inputs and outputs when connected with adapters to a Mac? Are the solution stable?