Sony mini-DV camera not connecting via Firewire Monterey 12.7.6 late-2015 27" iMac

All video apps (OBS, Quicktime, iMovie, etc) fail to see my firewire connected Sony mini-DV camera as a input when using my late-2015 iMac running Monterey 12.7.6. Security/Privacy settings are all set to Camera enable and the internal camera works, but not the firewire camera. There is no menu in Monterey about connected accesories.

The exact same camera, with one extra adapter to USB-C works perfectly on a new 24" iMac M4 running Sequoia. So I know that all of the camera settings (DV-IN to out) and cable/adpaters are fine.

I know Apple had a Firewire issue on Monterey 12.4 that got fixed in the next revision. The late-2015 will not update beyond Monterey. This camera and cable/adapters used to work on the 2015 iMac about 5 years ago an earlier OS.

Why am I bothering to use a 2015 iMac when I have the 2024 M4 you may ask. Well, the 24" M4 running Sequoia is crashing evertime I use the LifeFlix Version 5 video capture app. So, as part of their app diagnostics I was trying to run an earlier version of LifeFlix on the Monterey machine as a counterpoint.

So I'm at a dead end and will need to continue to give up on LifeFlix and digitize my old tapes with QuickTime, OBS or iMovie on the new 24" iMac.

I'm seeking any comments on:

1. Firewire dead on Monterey 12.7.6

2. LifeFlix V5 crashing on M4 iMac with Sequoia 15.3.1

Thank you.