How can I stop my Mac mini M4 from overheating?

Sounds like some services are still working while the fan is off in computer sleep mode.

for a similar case see > Mac Mini M4 Overheat while in sleeping mo… - Apple Community

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As a test

Turn On "Prevent automatic sleeping when display is off"

Set "Turn display off when inactive" to 5 or 10 minutes

Leave the Mac Mini On and only allow the display(s) to turn Off

Do not manually Sleep from the Apple Drop Down menu

Shut Down the Mac when away for a day or more

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For many years I have use MacFanControl on my iMac's and Mac mini's to monitor the temps and to slightly increase the fan speed when they are under heavy work loads. see > https://crystalidea.com/macs-fan-control

"How can I stop my Mac mini M4 from overheating?: [...]Recently I aware that my mac mini M4 gets warm to the touch even when I put it in sleep. Although at first I do some checking through the terminal by running the command 'pmget -g assterions' and the result shown to me is this:[...]"

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Troubleshooting Overheating Mac with Bluetooth:

A. Reset the Bluetooth Module:.

Use this command in Terminal

sudo pkill bluetoothd

Screenshot.

B. Use the Activity Monitor:

See what it taking the most out of the CPU and RAM. Is it Google Chrome? Or is is something else? To Find Out, use Activity Monitor. Then, right-click anything taking up high-percentage, selecting end this process.

1. Go to: Applications
2. Select: Utilities folder
3. Open: Activity Monitor
4. Click: CPU column
5. Click: Memory column

C. Single-Out this User:

Create an Administrator, and see if you get this issue. If not, then it is an issue in your current user. If so, then it is an issue with your entire Mac.

There's a free temp app in the App Store that works well: Stats. I'm running it on my Mac Mini M4 and the highest temp seems to be around 120 ºF with 14 windows open in safari and Mail open.

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

All Mac Minis will be warm. You would need to monitor the temps, using an app like TGpro to see the data. The fan will change speeds as required. My Mac runs about 110 degree F even at idle and no issue.

That one entry means nothing without knowing more about the system. It is perfectly normal to have assertions which prevent sleep. If you want to look at the sleep & wake pattern of the Mac, then run the following command instead as it will tell you when the system goes to sleep & when it wakes up including how long for each event & the reason for waking/sleeping:

pmset  -g  log  |  grep  -iE  'Sleep  |Wake  '

FYI, there are two spaces after "Sleep " and "Wake " which allows the filter to narrow the results just to the relevant log entries for the actual sleep & wake events themselves.

I have attached more detail on my Mini M4 Pro temps. This is while I am on the Web. However, I have my Mac sitting on a Raycue dock which also generates some heat.