actually u can get round fan from doing normal and hard susanoo brother dificulty.

and red gourd also same, u can find it from normal and hard difficulty. I can confirm this matters for sure.

From my experience, there is a high chance u will get red tool from doing it with team instead of doing it with solo (this is the case for strong player). But since its a rng, just do what u want to do

as for getting adv thread from SA expert difficutly, u can safety think its as a dream, i only got it 1x long ago. The drop rate like 0.00000000000000001 %.

I hope oasis listen to this matter and fix this quickly. We dont want shady business like it seems oasis wanna milk the spenders to buy adv thread from event /shop while they can get it free from SA.