Hi @Brad.Mulley, sorry to hear that you have this kind of issue.
Please confirm if when you tried to install Deezer on your iMac if you did the following procedures: 
-Go to www.deezer.com/download. ...
-Open your Downloads folder and double-click the app to start the installation process.
-Follow the steps to install the app.
-Once installation is complete, launch the app, login.

Dear Deezer team,

I think all Mac users know how to install a DMG file. Simply the the installation file is not opening with error as Brad mentioned

Have you guys ever tried the Deezer desktop app on Mac after developing?

Mine is 13.0 Ventura by the way.

attached screenshot

Problem fixed as below ;
 

Steps to Use:

1. Start by opening the menu on Apple and then tap on the "System Preferences" option.
2. Select the option of "Security and Privacy."
3. Now locate the General tab and tap on the yellow padlock, then make an entry of your passcode.
4. Now tap on the 'Allow' button. ... 
5. Click on the "Ok" button.

I think Deezer should pay me back for customer support which I am doing

I have the same issue and don't want to use something like the security turnaround protocol from the post above. All official apps should work without disabling or ignoring Apple system's protection.I’m having this issue for a month so my question is - do you ever test your apps?

I think you are drastically overestimating the average user’s tech familiarity. 

That being said, thank you for your contributions to the thread.

I also had the same issue. After downloading Deezer.dmg and putting Deezer in the Application folder, it didn’t open.

You can fix it this way and it is easy:

• Go to the Application Folder.
• Use the Ctrl button and the mouse for the menu to appear.
• There you can choose Open. Than another menu will apear there choose Open.
• And then you will always be able to open Deezer on your Mac.

My screenshots are in Dutch, but I think it will expain it all.