The block post is titled "Clean mount lists in Linux" not "Clean block device lists in Linux". I was demonstrating that findmnt can filter the source based on MAJOR:MINOR as a tangential, there was no attempt to "slip" anything in, hence the disclaimer.
You are correctly pointing out that it filters only the first loop device and doesn't support globbing. lsblk is clearly the better suited tool for the job you are describing and the reason I said "majority" in my first comment.
When doing a factory reset because of whatever reason, this becomes an issue as well. You cannot take screenshots of the bulk export QR-Code on Android because of FLAG_SECURE, so you need to work around that and take a photo of the screen with a different device to import from later.
Also, as of last week, there existed an issue with special characters when trying to import and the app would just freeze or not recognize the QR code pattern at all, so you better had backups of all your secret keys.
Both issues made me switch to Aegis and appreciate my past self backing up the secrets with KeePassXC.
You are correctly pointing out that it filters only the first loop device and doesn't support globbing. lsblk is clearly the better suited tool for the job you are describing and the reason I said "majority" in my first comment.