Back in the early days of D2, there was an event called faction wars. Over a week, you pledged your gameplay to a specific faction and were rewarded with themed armor and weapons. If you went above and beyond standard gameplay, you got additional ornaments to make your armor look cooler.
Under the new Armor Synth system, those ornaments, which are locked to those specific armor pieces, are not available for global unlock despite your having them in your collections. You can still get the look if you reacquire and use the specific armor piece, but ALL those pieces are sunsetted.
Bungie, please make those looks available in Armor Synth. Or at least re-release the faction armors, like you've done with the Future War Cult weapons.
Thank You.
EDIT 1: At the time of this posting, I had not read the TWAB for 5/13/21. I am now aware that D2 Year 1 armors are still being worked on and are pending inclusion into the Armor Synth system. Apologies.