Like Vanilla Tweaks' Armored Elytra, available for 1.20.6, 1.21(.1), and 1.21.4 You can combine elytra with a chestplate in an anvil, make sure you put the chestplate in the left slot. You can then ...

This repo contains the scripts and base resource pack. If you are looking for just the vanilla elytra texture while keeping capes activated, see the Releases page.