Firewire Devices and Apple Silicon/Ventura

I have been able in the past to connect FW400 and FW800 devices to modern Macs. Some of these devices are legacy devices and there is no point in telling me to upgrade them! Imacon, Hasselblad and Nikon photo negative scanners in particular. I am resigned to keeping a couple of old Macs around to keep them functional. But today, a new issue arose.
I have a 13" MBP 2015 that I have used as a server, connected to an OWC Mercury Elite, set to mount as JBOD. This copies one disk to the other three once each day, and an OWC Voyager naked disk enclosure is daisy chained via FW800 so I can keep offsite backups. All works perfectly, but it has been two years since I last replaced the battery in the MBP and it has begun to swell again such that I cannot click the trackpad. I was also able to connect them to modern Macs up to the last Intel MBPs and MBAs using the adapter series below - until today.
Having anticipated that it would die one day, I have an MBP 15" 2018 now running Ventura ready to replace the server. But when I try, my disks in the Mercury Elite will not be recognised or mount. They used to connect to it when I first set it up via FW800>Thunderbolt and then Thunderbolt>USB-C, using Apple adapters, when the MBP had Monterey.
Is this new for Ventura? I’ve worked around it for now by connecting the USB 3.0 output to an Apple USB-A to USB-C adapter, and I’ll have to buy a new Voyager for the naked offsite disks and connect its USB 3.1 output by a similar adapter.

They used to connect to it when I first set it up via FW800>Thunderbolt and then Thunderbolt>USB-C, using Apple adapters, when the MBP had Monterey.

FWIW, I just tested an OWC Firewire 800 (older “On-the-Go” model) w/ those adapters on my Studio Ultra and Ventura (latest “c” patch… :-) Seems to be working, mounted, wrote and read.

Hmm. Maybe it’s something to do with the FW controller in the Elite.

If the MBP/Ventura is not in play, how about resetting macOS to Monterey?

That would be an option, unless it is the peculiar FW controller built into the OWC Elite.
It seems to be working OK with the USB 3.1 interface, and a new Voyager is just $32 - cheaper than the Apple USB-B>USB-C dongle I shall have to use with it!