Occasional screen black out

Hi, I am experiencing on a new computer occasional screen black out (completely black) that last about 3 seconds. No idea what can be the cause. Anyone have any idea ? Monitor is also new and is Benq SW271, driven by HDMI cable. Here is my config , as output from inxi -v 8

System:    Host: antares Kernel: 5.9.16-1-MANJARO x86_64 bits: 64 compiler: gcc v: 10.2.1 
           parameters: BOOT_IMAGE=/boot/vmlinuz-5.9-x86_64 root=(hidden) rw quiet apparmor=1 
           security=apparmor resume=UUID=(hidden) udev.log_priority=3 
           Desktop: KDE Plasma 5.20.5 tk: Qt 5.15.2 wm: kwin_x11 dm: SDDM Distro: Manjaro Linux 
Machine:   Type: Desktop System: ASUS product: N/A v: N/A serial: <superuser required> 
           Mobo: ASUSTeK model: TUF GAMING Z490-PLUS v: Rev 1.xx serial: <superuser required> UEFI: American Megatrends 
           v: 1208 date: 07/21/2020 
Memory:    RAM: total: 31.25 GiB used: 6.07 GiB (19.4%) 
           RAM Report: permissions: Unable to run dmidecode. Root privileges required. 
PCI Slots: Permissions: Unable to run dmidecode. Root privileges required. 
CPU:       Info: 8-Core model: Intel Core i7-10700F bits: 64 type: MT MCP arch: Comet Lake family: 6 model-id: A5 (165) 
           stepping: 5 microcode: E0 L2 cache: 16 MiB bogomips: 92838 
           Speed: 4272 MHz min/max: 800/4800 MHz Core speeds (MHz): 1: 4272 2: 2713 3: 4623 4: 4459 5: 4260 6: 4568 7: 4606 
           8: 4581 9: 4629 10: 4571 11: 4129 12: 4283 13: 4600 14: 4602 15: 4403 16: 4644 
           Flags: 3dnowprefetch abm acpi adx aes aperfmperf apic arat arch_capabilities arch_perfmon art avx avx2 bmi1 bmi2 
           bts clflush clflushopt cmov constant_tsc cpuid cpuid_fault cx16 cx8 de ds_cpl dtes64 dtherm dts epb ept ept_ad erms 
           est f16c flexpriority flush_l1d fma fpu fsgsbase fxsr ht hwp hwp_act_window hwp_epp hwp_notify ibpb ibrs 
           ibrs_enhanced ida intel_pt invpcid invpcid_single lahf_lm lm mca mce md_clear mmx monitor movbe mpx msr mtrr 
           nonstop_tsc nopl nx ospke pae pat pbe pcid pclmulqdq pdcm pdpe1gb pebs pge pku pln pni popcnt pse pse36 pts rdrand 
           rdseed rdtscp rep_good sdbg sep smap smep ss ssbd sse sse2 sse4_1 sse4_2 ssse3 stibp syscall tm tm2 tpr_shadow tsc 
           tsc_adjust tsc_deadline_timer vme vmx vnmi vpid x2apic xgetbv1 xsave xsavec xsaveopt xsaves xtopology xtpr 
           Vulnerabilities: Type: itlb_multihit status: KVM: VMX disabled 
           Type: l1tf status: Not affected 
           Type: mds status: Not affected 
           Type: meltdown status: Not affected 
           Type: spec_store_bypass mitigation: Speculative Store Bypass disabled via prctl and seccomp 
           Type: spectre_v1 mitigation: usercopy/swapgs barriers and __user pointer sanitization 
           Type: spectre_v2 mitigation: Enhanced IBRS, IBPB: conditional, RSB filling 
           Type: srbds status: Not affected 
           Type: tsx_async_abort status: Not affected 
Graphics:  Device-1: Advanced Micro Devices [AMD/ATI] Navi 14 [Radeon RX 5500/5500M / Pro 5500M] vendor: ASUSTeK 
           driver: amdgpu v: kernel bus ID: 03:00.0 chip ID: 1002:7340 
           Display: x11 server: X.Org 1.20.10 compositor: kwin_x11 driver: loaded: amdgpu,ati unloaded: modesetting,radeon 
           alternate: fbdev,vesa display ID: :0 screens: 1 
           Screen-1: 0 s-res: 3840x2160 s-dpi: 96 s-size: 1016x571mm (40.0x22.5") s-diag: 1165mm (45.9") 
           Monitor-1: HDMI-A-0 res: 3840x2160 hz: 60 dpi: 163 size: 597x336mm (23.5x13.2") diag: 685mm (27") 
           OpenGL: renderer: Radeon RX 5500 XT (NAVI14 DRM 3.39.0 5.9.16-1-MANJARO LLVM 11.0.1) v: 4.6 Mesa 20.3.3 
           direct render: Yes 
Audio:     Device-1: Intel Comet Lake PCH cAVS vendor: ASUSTeK driver: snd_hda_intel v: kernel 
           alternate: snd_soc_skl,snd_sof_pci bus ID: 00:1f.3 chip ID: 8086:06c8 
           Device-2: Advanced Micro Devices [AMD/ATI] Navi 10 HDMI Audio vendor: ASUSTeK driver: snd_hda_intel v: kernel 
           bus ID: 03:00.1 chip ID: 1002:ab38 
           Sound Server: ALSA v: k5.9.16-1-MANJARO