This is my first post so please be gentle! I've had Samsung Galaxy phones for the last 6 years with no issues, but unfortunately that has just changed...
Hi. No, I never found a solution to this problem! And Samsung were almost no help. I couldn't even get through to them via their website. It seems to be set up so it's very hard to contact them and speak to someone. They didn't even respond to me at all until I Tweeted at them on Twitter and included their @ in the Tweet!
I currently use my Note 9 phone (128gb model) with no SD card as I don't want the hastle of a card being corrupted again. As I stated in my OP, I use Poweramp music player and after the phone corrupting 2 separate SD cards I had to put all my music onto the phone, which means that there are 2 or 3 copies of all of my songs listed in the app , but only the ones stored on my phone will play (the music app found the songs on the SD cards but they had been corrupted and wouldn't play, but they're still in the lists of artists & songs). This has meant that I have spent months having to manually delete all of the "copies" of songs that wouldn't play and there was no way to batch delete all the corrupted files from the list. I have literally 10's of thousands of songs so it's still going on whenever I find albums I've missed! It's maddening!
Samsung's best advice was for me to physically take my phone to a Samsung centre for investigation, but there isn't one in my town and I haven't had the time to spend a full day travelling to a differnet city and back, then taking the time for one of their staff to look at my phone and inevitably tell me to restore the factory settings and see if that makes a difference (which is almost a 100% certainty that they will suggest that first). Because if it doesn't make a difference, I'm back at square one and will have to go through the process of trying SD cards, then if they get corrupted again, manually deleting 1000's of corrupted files again!! It's taken me months to delete the majority of the corrupted files off and I'm not going through that again!
I'd rather just live with the phone's internal storage of 128gb for now as life's too short! Though that's not the point!
I'm not sure if this has anything to do with it, but when I had a Note 4 the SD card slot was a slot under the SIM card slot and when you put a SD card in it felt very securely in place. With the Note 9 you put the SD card in a flimsy pastic tray and it kept falling out before I finally got it to stay in, then inserted it into the phone. Maybe the tray isn't holding the SD card in place tightly enough and the connection keeps getting cut out? Maybe that could be causing the corruption?
Samsung don't seem to care at all and I've read that many people have had this issue but there doesn't seem to be a solution and Samsung have just swept it under the rug because they don't care about their customers as long as they're making money!
If you (or anyone!) find a solution please let me know!