iMac Photos won't import iPhone photos in Normal Mode

Maybe some 3rd party app intervenes? 3rd party virus apps and "cleaners" are the usual suspects. An EtreCheck report might provide more clue (set Full Disk Access for it):

Using EtreCheck to Troubleshoot Potential… - Apple Community

Getting rid of Login items was a great response to the Safe Mode analysis! Clearly something else is going on in your User account on the Mac. As Matti Haveri suggests, virus apps and "cleaner" apps are often responsible. EtreCheck may give you some clues.

You could also just make a new User and transfer stuff over, then delete the original User.

With new Silicon Macs PRAM resets are a thing of the past. Maintenance like that is done with a re-boot. But for Intel Macs

Reset NVRAM or PRAM on your Mac - Apple Support

And for the System Management Controller, SMC:

How to reset the System Management Controller (SMC) on your Mac - Apple Support

However, since the Mac works in Safe Mode, resetting these probably won't change anything-- but it doesn't hurt to try.

I think you ought to try setting up a new User account-- that separates you from all the old garbage. If storage becomes a problem, you can just delete the old user and be done with it. It's probably a good idea to make a good backup before any big changes.

LivingADogsLife wrote:

I ran EtreCheck and as you might expect, there is a long list of uninterpretable stuff in the Minor Issues.

To help troubleshoot your Mac, I would suggest that you consider posting the resultant EtreCheck report for us to review. (Note: The EtreCheck report does NOT contain any personal information.)

• *** Paste the report, using the "Additional text" option from the ASC editor's tool bar, in your reply. ***