Please note that the warning is there as your extension passwords do not meet the minimum security requirements of the PBX. Once you update your passwords the warning will go away. You can automatically regenerate the passwords using the "Regenerate" button from the extensions tab but please keep in mind that that will reset all extension passwords including the voicemail pin .
Also if you use the "Regenerate" button supported devices will re-provision automatically so will 3CX client. However legacy and non supported devices will have to be re-provisioned manually.
Unfortunately I cannot regenerate every extension because strong usernames are denied by one of our external systems.
The setting SHOWEXTWEAKPASS has no effect on the Exclamationmark.
If your systems do not support Strong Usernames - then ignore the warning.
SHOWEXTWEAKPASS is not even listen in my parameters. I think that was from v12 and perhaps not viable anymore.