Running OS Sequoia 15.3.2 on an M1 Mac Mini. Folder access error message?

You could search this community on:

Lightroom Classic does not have access to some Standard folders.

And you will find existing discussions on that,

Not to be entirely a wet rug, following is an example that probably solves  your MACOS issue:

• https://community.adobe.com/t5/lightroom-classic-discussions/lightroom-classic-latest-upload-missing-access-to-standard-folders/m-p/13141265
• https://community.adobe.com/t5/lightroom-classic-discussions/lightroom-does-not-have-access-to-some-standard-folders/m-p/13139725
• https://community.adobe.com/t5/lightroom-classic-discussions/lightroom-does-not-have-access-to-some-standard-folders-still/m-p/14246602

etc.

And those links point to:

• https://community.adobe.com/t5/lightroom-classic-discussions/quick-tips-how-to-give-full-disk-access-to-lightroom-classic-on-macos/td-p/12913413

and (if that does not work)

• https://helpx.adobe.com/lightroom-classic/help/setting-preferences-lightroom.html