I always thought it was OK to leave salted butter out. Been doing it for years never had a problem I can remember. I also don’t eat tons of butter so would guess I’ve left it out longer than two weeks
Today’s salted butter doesn’t have enough salt in it to preserve itself like that.
Back in like Oregon Trail days they would pack butter in enough salt to preserve it for travel, and people got used to the taste (hence why they still make the two types) but today’s butter is just not salty enough.
I also did that for years, with 5 people in the house we went through softened butter fast.
Then as kids grew up and moved out, I realized it was taking WAY longer to go through. I gave up and leave it in the fridge now. Then again, going through it much slower means that I’m buying much nicer quality butter 😁.