I tried to do a search for your problem, and apparently there is a problem with icons going invisible (but actually still there and you can click the space) that may be different from a problem with the icons not being there at all.
Here's one fix that involves your antivirus and removing Desktop from the protected folders list:
https://social.technet.microsoft.co...nned-icons-on-task-bar-keep-disappearingIf you are using Windows Defender as an antivirus, the above is probably not the problem, but if you're using a 3rd party antivirus this fix might help.
Some other potential fixes:
https://thegeekpage.com/fix-taskbar-icons-missing-windows-10/