Blackmagic Ultimatte Timecode

I’m trying to use a Blackmagic Ultimatte for keying. I can output from UE into the background layer input of the Ultimatte, but then there’s a latency issue (of a few frames). So instead I’m trying to go from the Ultimatte into UE - both with the FG and the Matte, then using the Matte to mask the FG for my composite.
With timecode (and genlock), my thought is that everything will then be nicely synchronized.

HOWever … UE apparently can’t read the TC coming out of the Ultimatte.
If I go straight from the camera into UE (via a Decklink 8K), timecode works in UE.
If I go from the camera into UE and back out through the loop out, TC works. If I put a Hyperdeck in between (to be able to see that the feed and TC are there!), it still works.
However, if I output from any other port of the Ultimatte (e.g. FG, Program or Matte) into UE, it doesn’t not read the timecode. I’ve also looped it through the Hyperdeck - which does show the timecode, of course. But UE can’t seem to read it.

Has anyone else had this issue?

How are people otherwise dealing with sync when using the Ultimatte??
Need to sync at least 4 things - the camera feed, the matte, the virtual camera view - and the camera tracking.

I am literally about to embark on this journey. Have you found a solution? another question. I initially thought I could use 1 hyper deck. Are people using 2 hyper decks to record the Camera footage through the ulitamatte and then the other deck to record the unreal virtual enviorment?

I don’t really check here frequently, sorry!
Did you get your Ultimatte working? Turns out that for some reason the Ultimatte turns the VITC timecode from the camera into LTC - which is what then goes into UE via the Decklink. It makes little sense. UE5.1 now sees whichever timecode automatically, so it works even if you don’t specify.

Has anyone solved this issue? We are struggling with the lag as well.