I'm not sure who is using the IF-FW/DM mk2 with Sequoia that you haven't messaged already...however, from some of those threads, you may have some prerequisites to overcome...first being, the knowledge and skillset to open/modify/install KEXT drivers and other system level work since (to my knowledge) there isn't native support since Mavericks officially, so I'm doubtful that a pre-compiled installer exists.
Secondly, if your MBP is on Silicon vs Intel, the driver CPU instruction sets are probably different and incompatible, not to mention, needing to use a thunderbolt 3/4 to thunderbolt 2 adapter followed by a thunderbolt 2 to firewire adapter to interface and then a Firewire 800 to 400 cable. Most Thunderbolt 3-2 adapters don't pass power, so I'm sure if others have successfully done that with the combination of adapters...I haven't had a system to test this yet (the firewire card that came in my latest DM is fried), so I can't do so myself.
You may be better off getting an external interface with ADAT I/o (or TDIF/AES/or combination) and additional expansion cards to then interface with your DM. You might also want to keep an older Mac or PC to run TM Companion, etc if you wish.
