I'm finished at this point so I felt like sharing. Made 1 milli in less than a hour.
Flashback 87 ~ 18k
Most feared 87 ~ 7k
For a 90 flashback you put in three 87 flashbacks and a normal 87. So 18k + 18k + 18k + 7k = 61k
Do this 3 times and but one more 87 flashback. This will now cost 61k + 61k +61 k + 18k = 201k
Put all the cards into a 92 flashback set and chose kerby Joseph. This site says he is going fur 240k but if u click an actually look it shows that he's actually going for 315k. After tax 70k profit Everytime. Also if you want just sell the 90 flashbacks instead for 120k that'll be 50k profit. Go check for proof.
You're welcome.
(Also I checked, only on PS5.)