Photos keeps freezing while trying to edit

When working with Photos, try to keep at least 10GB of storage really free, at all times, better more.

And if you are using iCloud Photos, I would wait, until new photos have been uploaded to iCloud or at least the syncing has started, before trying to work with the new photos.Since the Big Sur upgrade Photos is acting a bit strange, when I try to use the photos, while they are only visible in Imports.

Is your Photos Library.photolibrary still in your Pictures folder, or have you moved it to an external volume to save storage on your Mac?

Could it be, that you are running out of storage on your Mac? Check the free storage on your system volume and on the volume, where your Photos Library is stored, if it is not on your system volume.

Where are you keeping the Photos Library?

Are you perhaps using iCloud Photos?

There is one problem with "Available" storage. This is much too optimistic, because it includes storage that can be purged, but is not yet free. If you select your system volume in the Finder and use the key combination ⌘I to open the Info, it will show you the available storage and in parenthesis the amount of "Purgable", that is included in the available storage, but not yet free. The difference should not be smaller than 10 GB at least, or you are having a storage problem.

For example: I am using 1.3TB of of my system volume, 13.09 GB could be purged, if need be. How much of your available storage is just pursuable, but not yet free?

You may want to check, if there is an updated driver available for your printer from HP. After the Big Sur upgrade all older 32-bit applications have been deprecated. For some older software the developer certificates may have expired.