The Quick Commands listed at https://vivaldi.com/#Features are incorrect for Windows version Toggle Panel CTRL-P means print Download Panel CTRL-D worked Bookmarks CTRL-B didn't work Also interesting the the Quick Commands explanation was a unselectable image, I would like to be able to copy/paste any text on a page, especially yours Otherwise, interesting, more help pages and a help button would be useful.
I'm using latest snapshot so I don't know (can't remember) if those commands were working on the tech preview. It's still very much work in progress so things on the website might not be up to date. Either way there is no problem to assign your own shortcuts to things you've mentioned and dozens of others. Just remember that if some key combination is used for one thing and you assign it to other thing you will get some nasty conflicts. To avoid it make sure that shortcut you've chosen is not already used.
Toggle Panel was and is F4, even prior to the TP - in Windows and Linux. Perhaps that's from a Mac version.