Budgie user here, looking at the issues & (work around) solutions after update
Issues
Applications not loading existing account profiles/settings due to keyring issue (for me it's Vivaldi)
There is something similar logged for electron apps https://github.com/BuddiesOfBudgie/budgie-desktop/issues/747
Qt applications reverted to light theme
Custom key bindings reset back to default has been logged https://github.com/BuddiesOfBudgie/budgie-desktop/issues/745
Work arounds
Used @palto42 work around (Thank you), see their above post to create 90-gnome-keyring.conf file that resolved the keyring issue for Vivaldi
This incidentally also resolved the Qt applications back to dark theme
Used the below terminal command to get my previous existing custom key bindings back
dconf write /org/buddiesofbudgie/settings-daemon/plugins/media-keys/custom-keybindings "$(dconf read /org/gnome/settings-daemon/plugins/media-keys/custom-keybindings)"
Rebooted & work around persisted
Note
I can't confirm @palto42 work around for electron applications, as the only electron application I use is element which worked for me after initial update
I had no issues with budgie applets I have installed
Hope this helps