@wizard I managed to open Chrome settings inside Vivaldi (Vivaldi normally handles opening vivaldi:// URIs and opens their own settings page, but you can still access those by opening spell checker settings — right click inside a text field, "Spell check" -> "Language settings")
This will get you to Chrome settings, the URI it opens is not handled by Vivaldi for some reason.
@tdemin @wizard you can open those just by typing "chrome://settings" into the address bar (i'm not completely sure, but it works for me). some features, like cookies settings exceptions and some privacy options aren't implemented in vivaldi's native settings dialog, so i use chromium's.
also, e. g. extensions page is chromium's default, too, vivaldi hasn't implemented its own yet.
@tdemin @wizard it's weird that "chrome://" page redirects you to the "vivaldi://" page, but still opens the chrome page. while typing "vivaldi://" directly takes you to its own page. i. e. you can open two tabs, have the same address in both, yet one will be vivaldi settings and the other will be chrome settings!