Come help me then, we'll remind and motivate each other. I don't know how to even get close to some of the things you're saying (I never used data backs), and I did use command blocks for some basic exchanges of custom with custom items but it was cumbersome and had many limitations. Nothing like a config or a sign or placing items in item chests or regular chests and having them recognized. I keep searching for newer and better solutions. Yes I'm excite we can make so many cool items with so many variables, but I want my players to have more options too in why they would acquire/craft them. And right now I'm not looking forward to implementing the way we did some limited exchanges earlier, because it's a lot of work and a lot of frustration, and not very worth it. And I would learn to script but at my age I need a bit more guidance and collaboration to get me through at least the early learning curve phase. Otherwise it's unlikely to happen. I'd be happy with even some discord collaboration but I'm not at a point in my life where I'd just sit there alone for hours learning it by myself (not all of it anyway).

Remind me to remind you to remind me to... ;)

This can somewhat be done right now, and the secret are datapacks. In specific: a datapack with specific crafting recipes. Now; last time I looked into this the whole setup was limited to vanilla items only (so: I could set up a recipe to craft a command block, but I could not do the same for a player head) but I don't know how much has changed here. And of course there's command blocks and functions which can also do a lot :)

Add functions into the mix which can easily use any type of command you need and well... there might also be options to script some things yourself. Food for thought perhaps?