This is the most common issue that I have found online and the 5w30 was the most common recommendation I saw. I'm currently waiting for the maintenance info from the current owner. He claims to have had the car totally gone through at a Subaru dealer when he bought it in 2019. It seems like he may not hurt for money so it's very possible that he had a lot of things repaired/replaced. He was having it prepped for his teenage daughters.