Latest Edge download and history icons missing in tool bar and not available in appearance in settings

To follow my steps, you first need to allow hidden files and folders to be visible in the Windows Explorer settings. Then in your user folder you will see a dimmed folder called App Data. Open that and go to Local. Then go to Microsoft. Then delete the Edge folder. On a pc where Edge has the icons visible, go to the same folder but instead of deleting it, copy it to a flash drive and the plug it into the one that has the issue. Copy the new Edge folder to where you deleted the old one.

Same issue here. Strangely, I do have the buttons in the Edge Dev version. Deleting and/or copying over the %localappdata% settings for Edge works for one Edge launch, but upon close the buttons disappear again.

Exactly the same behaviour described by @citrixscu here: "Deleting and/or copying over the %localappdata% settings for Edge works for one Edge launch, but upon close the buttons disappear again.".

... download and history icons missing in tool bar 

I don't have a solution, I'm afraid, but I'd mention that when the new fly-out panels were first introduced several months ago, their presence was governed by start command parameters. I wonder if those now no longer seeing the panels and their associated icons somehow have remnants of these parameters active. To find out, open edge://version in a new tab. The start command is given on the line labelled Command-line:

Do you see any reference to ms...Hub?

Similarly, there may be switches added to the command line of the shortcut used to launch the program. that's worth checking, too.

This is good insight, it is similar to the article I posted before, where it says how to add switches to remove things but not sort of add them back... Seems like this might be the right track.