Windows 11 Insider Dev channel build 22610
If Start11 taskbar enhancements is activated then all systray icons disappear except for speakers volume and internet connection. This is similar (but worse) to a known problem with this build where just the hidden icons disappear.
The Microsoft update wasn't ready / pushed out too soon. I used the "go back" button in the recovery options in settings myself. Maybe next week it will have a "hidden icons" button.
Exactly why they rushed the dev build over to beta I don't know when they are still updating the two in sync. It was nowhere near ready to move from the dev channel in my opinion. I have found the recent builds to be somewhat prone to crashing.
The issue is being triggered by the MS one. We actually fixed the system tray icons on the taskbar issue on Win11 dev last week before this MS update came out as it is linked to the hidden icons button being hidden. An edge case as nobody would normally hide that button and it only happens on dev/beta channel Win11 builds, but we didn't expect Microsoft to then release a build with that broken!
A perfect demonstration of why we say don't use dev/beta builds however.
Whenever a build newer than 1.22 is released there will be a workaround for the missing icons on the taskbar (not the hidden icons button). I cannot say when this will be released however.
My advice to those who run into this issue is roll back to the previous build of Win11 dev/beta or disable enhanced taskbar or live with the issue until the next MS update.