Possible hardware issues aside, do a complete virus scan and install tinywall free firewall that lets you block internet completely except as you allow. It ought not be doing anything in sleep mode.
https://tinywall.pados.hu/
+
+
Other possible non-hardware causes you might have: have you signed up to allow use of your machine for distributed networking for such things as cancer research, covid, or other remote access during idle time? Hijack for bitcoin etc. mining? It may or may not be activity you authorized if so.
Possible hardware issues aside, do a complete virus scan and install tinywall free firewall that lets you block internet completely except as you allow. It ought not be doing anything in sleep mode.
https://tinywall.pados.hu/