unwanted standby

Hello everyone,

Since updating from 19.3 to 21.1, I observe a surprising behaviour.
I use an ASUS laptop, always closed, connected by HDMI to a 27" screen.
Previously, when I turned off the screen, the PC continued to do its job in the background for several days (network activities).
Since installing 21.1 and despite having disabled sleep via control panel, the PC goes to sleep.
I found a workaround: I open the laptop, I turn off the external screen then I close the laptop.
With this procedure, everything is fine.
Which configuration files are responsible for suspending?
I like the GUI but I like typing directly in the text as well.

Thank you for your kind help.

Here is the configuration:

System:
Kernel: 5.15.0-69-generic x86_64 bits: 64
Desktop: Cinnamon 5.6.8 Distro: Linux Mint 21.1 Vera

Machine:
Type: Laptop System: ASUSTeK product: GL553VD v: 1.0
serial: H9N0CV10Z86838D
Mobo: ASUSTeK model: GL553VD v: 1.0 serial: BSN12345678901234567
UEFI: American Megatrends v: GL553VD.308 date: 04/29/2019

CPU:
Info: quad core model: Intel Core i7-7700HQ bits: 64 type: MT MCP cache:
L2: 1024 KiB
Speed (MHz): avg: 800 min/max: 800/3800 cores: 1: 800 2: 800 3: 800
4: 800 5: 800 6: 800 7: 800 8: 800

Graphics:
Device-1: Intel HD Graphics 630 driver: i915 v: kernel
Device-2: NVIDIA GP107M [GeForce GTX 1050 Mobile] driver: nvidia
v: 525.105.17
Device-3: Realtek USB2.0 HD UVC WebCam type: USB driver: uvcvideo
Display: server: X.Org v: 1.21.1.4 driver: X: loaded: modesetting,nvidia
unloaded: fbdev,nouveau,vesa gpu: i915 resolution: 1920x1080~60Hz
OpenGL: renderer: Mesa Intel HD Graphics 630 (KBL GT2) v: 4.6 Mesa 22.2.5

Network:
Device-1: Intel Wireless 7265 driver: iwlwifi
IF: wlp2s0 state: down
Device-2: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet
driver: r8169
IF: enp3s0 state: up speed: 1000 Mbps duplex: full

Info:
Processes: 298 Uptime: 16h 37m Memory: 23.36 GiB used: 3.77 GiB (16.1%)
Shell: Sudo inxi: 3.3.13