For that matter, do the "dig a pit, put a roof on it, and smack Yagluth in the stomach" cheese, but bring a bow and a couple thousand arrows. At 10,000 hp, 75% pierce resistance means you would need something like 19+ stacks of wooden arrows assuming you never miss... and cheesing the AI means zero incoming damage potential while you burn through 2 full chests of arrows (and quite a few bows, too... at least 9 crude bows, by my count)... and that's also before factoring in regeneration.

According to the math at https://valheim.fandom.com/wiki/Skills that's about 2,728.5 "bows" XP; enough to hit level 44 in bows if you never fired one before the fight... and still not factoring in regeneration, which could very well make the fight impossible to finish without switching to a weapon Yagluth isn't resistant to.