With the saved hotbars, armor that have had experimental armor trims applied will not appear with the trim components in other worlds.

While these trims are not intended to be viewed in versions without the experiment, items like the mace have an addendum that it's disabled. While it may be annoying to have the entire armor piece be disabled you could have text that shows up on the side of the armor trim text saying disabled while ingame it loses its attribute visually while still appearing on the description as disabled.

Recreation steps:

1. Save a trimmed piece of armor with the trims Bolt or Flow.
2. Join a world with the 1.21 experiment disabled.
3. Open the Saved Hotbars menu.
4. Take out your measly 10 attribute enchanted leggings.

Attached is an example of saved hotbars disabling with the mace and the trimmed leggings.