Can the Imac and Safari be set back to default settings, and in that case how?

On a hunch as we are missing some important clarity from the original question

Too set the computer and therefore Safari Application back to Default Setting

What to do before you sell, give away, trade in, or recycle your Mac - Apple Support (CA)

Although you may what to Keep the Computer the above method would achieve the desired results and return Both the Computer and the Operating System back to Default as in Like Out of the Box Experience

RS1250 wrote:

I have made so many changes to my iMac Retina 5K 27-inch 2020 and in Safari that I want to reset it to factory/default settings, but still with the latest updates for the iMac and Safari.

Could it be done without deleting photos etc on the iMac?

You have everything backed up to an external drive, right? Then there's no problem.

If you don't have everything backed up, make that your priority.

How to back up your Mac - Official Apple Support

This aspect of OP question could be problematic ?

" Could it be done without deleting photos etc on the iMac? "

Pictures, if rolled back to macOS 11 Big Sur while TM Backup is from Ventura ?

That I am not sure about ?

1) First: make absolutely sure that you have an up to date Time Machine backup.

Better yet, you should also have a second backup, as you are about to erase the data from your mac.

2) In System Settings->General->Transfer or Reset, choose "Erase All Content and Settings".

3) Your mac will restart as if for the first time. During the initial setup, you will be asked if you want to bring data - choose "From another Mac, Drive or Time Machine backup", select your backup from step 1

CRUCIAL: elect to bring back ONLY the user accounts

(otherwise you'd just get back to where you started)

You will have all your documents, photos, mail, music, etc

Any system modifications will have disappeared.

You will need to install any non-system applications, from the App Store or their developers.

For more details, see:

What to do before you sell, give away, trade in, or recycle ...AppleOfficial Apple Support › en-us

You may need to explain a little more what you are trying to achieve.

Writing an effective Apple Support Communities question

If you haven't already, you may want to spend some time reviewing the user guide:

macOS User Guide - Apple Support

For the sake of continuity, please see the other posts: https://discussions.apple.com/profile/RS1250/subscriptions

++2

Was going to make mention in earlier posting but your method was far superior