New Magic Mouse temporarily disconnects

I don't see any of the usual suspects in the report. However, you do have PACE Anti-Piracy installed and it's not needed and can interfere with system performance.

There is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This documents describe what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community and Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support.  

There are no known viruses, i.e. self propagating, for Macs.  There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.   

Anti Virus developers try to group all types as viruses into their ad campaigns of fear.  They do a poor job of the detecting and isolating the adware and malware.  Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.

There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is designed solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

Uninstall PACE according to the developer's instructions.

Just to rule out interference, do you have any other Bluetooth devices nearby? How about your wireless router?

Ref: Resolve Wi-Fi and Bluetooth issues caused by wireless interference - Apple Support

Download and run Etrecheck. Be sure to give it Full Disk access before running.

Copy and paste the results into your reply. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support  to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

Copy the report

and use the Additional Text button to paste the report in your reply.

Then we can evaluate the report to see if we can determine the cause of the problem.

Hi,

it might be probable that the problem is your iMac, maybe you can try to connect your mouses to a different device ( MacBook, iPad or another iMac) and see if it does the same issue.

if it works fine the problem is the Mac. You can go in every Apple Store or Authorised Apple Resellers in your country and they will find the best option for you.

Andrea

I can get my Magic Mouse, Trackpad and Keyboard to disconnect with a few seconds by placing my iPhone SE2020 on the keyboard tray. Almost reliable enough to be a party trick!

Right now it is about 18 inches from the KB tray and everything works fine.

Do other iPhones affect the keyboard the same as yours?

Does your iPhone affect other wireless keyboards similarly?

I have a Matias Backlit Bluetooth Keyboard with my iPhone right on it at the edge without a problem.

I have a similar problem but my mouse is the older version with replaceable batteries. I recently bought a magic keyboard to replace my wired Apple keyboard. I almost never had a problem with my mouse disconnecting but since I added the new keyboard it happens at least once a day, usually when I first use the Mac mini. I do have an Apple Watch and iPhone and will see if keeping them distant helps.

Have you installed and run any "cleaning", "optimizing", "speed-up", anti-virus or VPN apps on your Mac?

You're very welcome!