How do I PERMANENTLY show hidden files jn MacBook?

This might be a good time to reboot the computer ins safe mode and let the OS do its housekeeping chores.

Safe mode will often correct weird software behavior by forcing the OS to clear caches, do disk repair and other self-maintenance and housekeeping and temporarily disables third-party mods.

How to use safe mode on your Mac - Apple Support

Have you installed any anti-virus, cleanup, optimizing or VPN applications?

The Mac needs none of these and apps of this type often are the culprit when strange behavior is happening. If you have any of these installed, it is generally recommended that you uninstall them per the publisher's guidance.

Please see the thread I linked above. The discussion includes using Terminal command chflags to change this attribute of hidden files. This is different than simply adding or removing a leading period to the filename.

To show hidden files on macOS, use the keyboard shortcut Command + Shift + Period (.). This will toggle the visibility of hidden files and folders in Finder windows. Hidden files are typically denoted by a semi-transparent icon. To hide the files again, simply press the same shortcut (Command + Shift + Period). 

They are hidden by the designers of the operating system, usually to prevent visual clutter by items you can't do anything with, and also to protect the os from users who don't know what they are doing. And before you say "but it's my computer" yes, it is. But it's not your Operating System, that is licensed to you - as is - for your use. You never own it - just like every other piece of software. You cannot do what you want in this case.

Stang2000 wrote:

Those hidden files were created by me. The OS doesn’t own my files.

The OS doesn't own your files, but that doesn't mean that you get to alter the way that the OS works, in any way that you like, at any time. If you are naming or marking your files in such a way that the OS believes that the files should be hidden (e.g., by using a leading '.'), and you don't want files hidden, well, maybe stop naming / marking files in that particular way.

"Doctor, it hurts when I do that."

"Then don't do that!"

Sounds like you have some personal files that somehow got flagged as to be hidden. Yes, you can change that for particular files and folders.

Ref: permanently display hidden folders in fin… - Apple Community

I would also be asking what caused those files to be hidden. Weirdness.

Stang2000 wrote:

I have no clue on the cause of those files being hidden. It’s all of a sudden.

MacBook Pro 14″, macOS 15.6

To be proactive you can file a bug report / submit your Apple Feedback here: Product Feedback - Apple

You're welcome.

I understand that Kaspersky may appear to work fine, but apps like that are notorious for causing interference. There are no "viruses" that will affect the macOS, especially now that the OS resides on a secured, read-only volume. About the only anti-malware application that gets any recommendation here in the Community is Malwarebytes. Its free version allows you to run the occasional manual scan and it doesn't have to be always-on and running in the background.

Given that these now hidden files reside on an external drive, have you tried running Disk Utility's First Aid on that drive and its volumes? There may be some odd directory corruption going on.

How to repair a Mac storage device with Disk Utility - Apple Support

Is there any commonality of these files that have been changed?

Are they of a particular file type or do they belong to a particular application?

Stang2000 wrote:

I have Kaspersky installed for 2 years and it works fine all the way.

https://dmarcreport.com/blog/everything-you-need-to-know-about-the-us-ban-on-kaspersky-antivirus/

https://www.mcafee.com/blogs/security-news/the-kaspersky-software-ban-what-you-need-to-know-to-stay-safe-online/

Third party AntiVirus is not recommended— it typically does nothing but add issues to the macOS and competes directly with Apple’s own built in security:

macOS antivirus - Protecting against malware in macOS - Apple Support

macOS - Security - Apple  macOS - Security - Apple

Apple Platform Security - Apple Apple Platform Security - Apple Support