As with most modern studio devices, all those boxes you mention do not use incoming wordclock directly, but re-generate it in order to minimise the jitter. These days, wordclock is used to to keep the clocks in individual boxes running at the same rate rather than necessarily placing all the clock edges at exactly the same instant. Bearing this in mind, in terms of clocking and jitter, you should be fine using the UFX as the wordclock master with all the others as slaves.

That leaves the question of long-term timing accuracy, and it could be that (say) the Mytek clock has a greater accuracy specification than the RME ones. However, in the work I do, I lock the box clocks so they run at exactly the same rate, and run that way unless the current project is sensitive to other long-term timing issues. This has only come up for me so far when I am syncing either with video or with reel-reel tape decks. Both of those cases need special consideration.

Nice looking set-up. Marco!

As usual, Bos has solid advice. (y)

To add my two cents on clocking. As some may recall, I had a pretty awesome setup with a lot of outstanding gear and converters. Note: I wasn't doing A/V but if I was to do it all over again, I would clock exactly the same. Note: I also owned the ridiculously expensive Antelope Audio 10M that I sold with a big smile.
Being said: I found the best clock to be the internal clock of the interface on its own pcie port.

Thanks for your answers guys !
Always nice to confirm things.
I wish you a great 2021 !! Health and passion !

Nice rig there Marco. Lots of clocking opinions available and those here among us are some of the best anywhere.

That being said, I always clocked as Chris said. My Omni was the central distribution center for everything and became the master.

Now with the new stuff I've added I also added a clock as I was simply branching out too much and I felt with larger sessions the jitter was becoming audible.

I added the Black Lion Micro-clock MkIII XB. I can tell the difference