This one is simple in concept, but I can imagine it may be difficult to code. Other people have mentioned timers for dismantling things, and I'm going to assume that it will happen. I won't really dwell on that. Instead, let's look at a couple of nice quality of life changes.
First, while we I'm interacting with something, highlight it. Make it green? Or just make the outline easier to notice. I hate dismantling the wrong thing, because misread triangle as square. Hey. They're both polygons, cut me some slack!
Second, while I've got dismantle selected, highlight all of the things which would be affected by the action – maybe in red. If I've got a pillar set to destroy, I want to know which ceiling tiles – or crafting stations – are coming down with it. And make them visible through terrain! It's your own base you're wrecking, so it's awful to get surprises.
Finally, along the same vein as destruction, when placing pieces, highlight the existing piece that you're about to snap into – possibly blue? This way, you can see exactly what that stupid gate is trying to hook onto. Or, you can finish that pillar inside the terrain where the ground box doesn't mesh with the the 3D model, so you've built into the wall.
As a bonus thought, maybe give a way to show the tracery of the grounding. Say I'm about to place a pillar, and it looks like it's connected to the one above it, but is it also connected to the floor? Won't know 'til I go back to the top and fail to place my stairs, for the third time.