If you can't find the quiver recipes, it is almost always a loading problem.
Quick checks
1. Is Supplementaries installed? The data pack only adds recipes for the Supplementaries quiver. Without the mod, the recipes have nothing to craft.
2. Is the pack enabled? Run /datapack list and look for it among the enabled packs. If it is only listed as available, enable it with /datapack enable and the name shown in the list.
3. Did the game reload? After adding the file to a world's datapacks folder, run /reload or rejoin the world.
4. Is the file in the right world? Data packs are per world. A pack in one save's folder does nothing in another save.
On a multiplayer server
1. Place the data pack in the datapacks folder of the server's world, not in your own client's saves.
2. Restart the server, or have an operator run /reload.
3. Every player still needs Supplementaries installed as usual.
Recipe still hidden in the recipe book?
The recipe book may not show a recipe until you have picked up one of its ingredients. Gather some basic materials and search for quiver again. If you have cheats enabled, /recipe give @s * unlocks every recipe at once. If other items seem changed, look at your other packs. This one only adds the two quiver recipes and leaves everything else alone.