I'm experiencing the same: after a few month of usage my NTFS USB drive stopped to be mounted (RPi, LibreELEC 11.0.3)
dmesg shows no problem. Attaching it to a Windows machine problem is reported, having fixed them and reattaching to the RPi mounting works again. I suspect the appearence of this problem may be connected with accessing the drive via samba.
The same drive was formerly formatted to exFAT to ensure compatibility with the Windows world, but it showed the same problem. The disk become so corrupted that a lot of data have been lost (fortunately nothing irreplacable). That's why I'm trying now NTFS that may handle recovery a bit better.
If it is somehow really connected with samba, then perhaps not even using ext4 could help?
I did think about using ext4, but interoperability is hard in a Win/Mac environment.