Not sure any of what I'm suggesting below is viable or even possible. But thinking what about being able to create a Training Dummy that you can train your skills on. It would have to have durability so eventually after so many hits it does become unusable/on a cool down.Maybe you can only select one skill to train and only get a few skill points each time and to use the training dummy again you would have to wait so many days/week in game (you can't sleep through the nights either to progress the time). Or have so many trophies to give it, or have to have so much of a type of wood to repair it. Have it locked in that it needs to be by at least near a level 4 or higher workbench and you can only have one (sort of like Maypoles). If you take it down or want to move it can't be built for another month. I'm sure someone will figure out a way around the time restrictions, but this would give some of us playing in Survival PVE an alternate means to get our skills up (bow,swords, etc.) where it might be difficult to level them on an ordinary basis if you're a little less skilled than normal. (Can't hit a barn door with bows to save my life even when being sneaky).
Source: https://www.reddit.com/r/valheim/comments/12yy6eb/suggestion_training_dummy/
