After opening Battle.net, GPU Usage spikes to 100 percent every ~10 seconds. I have narrowed this issue to the Battle.net desktop app and disabling hardware acceleration does not fix the issue. Even after closing the app and making sure to kill the process in task manager, GPU usage still spikes to 100 percent every 15-20 secs, the only fix is to reboot. Again this is 100% battle.net, as I can run my PC for hours and play non Blizzard games and this never happens until Battle.net is opened. I have run multiple passes of different antivirus software and nothing ever gets flagged. I found a 4 year old Reddit forum with people talking about the same issue, but no fix was ever posted there either.
Edit:
System specs
Ryzen 5 2600x
32 GB Ram @ 3466 (downclocked from 3600 XMP2)
RX 580 20.9.1 Drivers
No Overclocks
Windows 10 Pro