Parmandur
Book-Friend, he/him
I'm not sure why you're talking about combat or fights. I didn't post an example of a fight; I posted an example of reforging a dwarven artefact.
I'm also not sure whether you are asserting or denying that 5e has a crafting resolution system.
If it is not a fight, exploration, or social interaction, then it is downtime, and downtime structures (of which there are multiple suggested approaches) would apply as judged neccessary by the DM.
There are crafting suggestions, but it is left to the DM to work in to taste.