Disk Utility problem when formatting external SSD:s or faulty drive?

Disconnect all other external devices in case one of them is causing a problem. You may also want to try booting into Safe Mode in case some third party software is interfering with the normal operation of macOS. I know this may sound crazy given you have two T7 SSDs, but they may be utilizing a different USB chipset (more of an issue with M1/M2 Apple Silicon Macs).

Make sure to connect the SSD directly to the Mac. Try using a cable from the other working SSD.

Try erasing the physical drive as MBR (Master Boot Record) partition and exFAT to see what happens. Then try erasing it again with GUID partition & APFS like you were before. Sometimes a drive may have some information or partitioning issue which Disk Utility cannot handle and trying a different layout may overwrite the part causing the problem.

Another option would be to use the command line to write zeroes to the beginning of the drive to destroy the existing partition table which will hopefully eliminate whatever is causing Disk Utility to behave oddly here. I highly recommend you disconnect all other external drives when attempting this procedure since if you select the wrong drive identifier for this process you will end up destroying data. Use Disk Utility to get the drive identifier for your 1TB external drive...in your first screenshot it was "disk5" at the time, but this drive identifier can change each time the drive is connected, so check just before issuing the command to write zeroes. In my example, I will use "diskX", but you will replace the "X" with the correct number for the drive.

First unmount all volumes on the drive "diskX" (remember to replace the "X" with the correct drive identifier):

diskutil  unmountDisk  diskX

Now write zeroes to the beginning of the drive identified as "diskX" (remember to replace the "X" with the correct drive identifier):

sudo  dd  if=/dev/zero  of=/dev/diskX  bs=100m  count=10

This second command will prompt you for your admin password. Nothing will show on the screen as you type the password, so press the "Return" key to submit the password.

If this completes successfully, then you should be able to use Disk Utility to erase the physical drive like you were originally trying to do.

You can also try partitioning & formatting the drive on Windows/Linux or perhaps an older Mac to see what happens if you don't want to use the command line. Normally I don't recommend using the Samsung proprietary software, but the Samsung Magician software may have an option to reset the SSD (may be called a "Secure Erase) which can sometimes fix an SSD by resetting an SSD to factory defaults.

Greetings vino1103,

If the physical health of the drive is in question, you can attempt to run First Aid and see if any errors are reported.

1. In the Disk Utility app on your Mac, choose View > Show All Devices.

If Disk Utility isn’t open, click the Launchpad icon in the Dock, type Disk Utility in the Search field, then click the Disk Utility icon.

Note: If you’re checking your startup disk or startup volume, restart your computer in macOS Recovery. See the Apple Support article About macOS Recovery on Intel-based Mac computers. Next, select Disk Utility in the macOS Recovery window, then click Continue. If you check your startup volume (Macintosh HD), make sure you also check your data volume (Macintosh HD - Data).

2. In the sidebar, select a volume, then click the First Aid button.

3. In the First Aid dialog, click Run, then follow the onscreen instructions.

4. When the First Aid process is complete, click Done.

5. Repeat steps 2 through 4 for each volume on the storage device.

6. In the sidebar, select a container, then click the First Aid button.

7. In the First Aid dialog, click Run, then follow the onscreen instructions.

8. When the First Aid process is complete, click Done.

9. Repeat steps 6 through 8 for each container on the storage device.

10. In the sidebar, select the storage device, then click the First Aid button.

11. In the First Aid dialog, click Run, then follow the onscreen instructions.

12. When the First Aid process is complete, click Done.

Repair a storage device in Disk Utility on Mac - Apple Support

Thanks.