self explanitory

You can already do this, using the Components tab in the settings!

• Either you can set health / armor etc. ("Reveal [x] when...") to "Always", then they will be static while the hotbar can move.
• Or you can set them to "Disabled", and configure the distance they move out by, such that they remain visible when the hotbar is hidden. For this, try values between 20 and 25. If you use this, you probably want to configure the distance that status effects move by back to the default of 60. This can be done using the "advanced component settings".

The first option reflects exactly what your title said, while the second option is a bit cooler and similar to how the old head-down display mod worked.

Let me know if either of these options work for you :)

Closing this issue as I believe it can be done already; feel free to reopen if these solutions aren't sufficient for your use case.