The only way is modding at the moment as already suggested. The easiest one you can use is Valheim Plus. It's basically "set and forget" and it's kept up to date by the mod devs who made it, particularly after patches and game updates. I use it for a few QoL things but you can change just about everything about the game in it. For what you've indicated you want to change, this can be done with V+ no probems. It's very easy to set up too.

If you want to spawn in a surtling spawner in the black forest you can use a devcommand to do it. (Don't recommend it though. LOL) But yes, if you don't want to use any mods, then you can use the devcommand console to spawn things in if you're playing locally on your computer.