Often, developers wander off to "make an engine" partially as an excuse to put off making those scary decisions. But an engine isn't a game and if you want to ship something people can play (and not just make games themselves with) you do have to make that choice.
You've made an insane amount of progress, but I wonder if you're struggling with this too. If I can make two suggestions that might help:
1. Realize a negative choice has positive value.
Every idea or feature sounds cool, so the default answer to "Should I add ___?" or "Can the player do ___?" or "Can the engine support ___?" is going to be "yes" because it all sounds fun. But the end result is something that takes infinite time to produce. Your time is finite.
It takes courage, but I find I make better progress when I deliberately allow myself to choose not to do something. Remember, any feature you omit pays you back in the most important currency: time. By saying, for example, "No multiplayer", you're saying "Yes" to a lot of other features you will now have time to implement.
2. Make the game that only your engine can do.
You're in an unusual position in that you already have a very interesting, unique engine. Most developers out there just have half-baked clones of existing engines.
When you're trying to figure out what kind of game to build on top of that engine, focus relentlessly on the kind of gameplay your engine, and only your engine can support. For me, that's rich, detailed, destructible terrain. If it doesn't take advantage of voxels, cut it.
Looking at the videos over the past year, I see lots and lots of basic character animation. Every game engine can do that. It's not interesting to see yours can too, and it takes (took) a ton of your time to do it. Don't spend time catching up to other engines. Spend time building on top of what you already have.
I don't care if a character in the game is a simple billboard—I actually think billboard characters would look nice with the pixely voxel style—I'm coming to your engine for the terrain. Everything else is secondary.
Good luck! It's been inspiring watching you make progress on this.