Almost all the browsers that I have tested have their update agent running independent of the browser and not all can be disabled as it can be done in Vivaldi or warn if there is an update, just update silently.
This can be a problem if you have several browsers installed, all with the Update running, without the user noticing, unnecessarily using resources and bandwidth.
This is why I always deactivate it in the browsers I have, either in the corresponding configuration or remove them from the Start with the Task Manager, if the browser does not offer this option.
It is very easy to look from time to time in the browser menu, if there is an update available and install it if so with a simple click and when it is convenient to do so ..

There should be 2 options:

update every x time period (not too important) update if there is no image (relatively more important)

@Ayespy https://forum.vivaldi.net/topic/78371/vivaldi-and-automatic-updates/30?_=1660409541003

Vivaldi on OS X MacOS uses a popular third-party software update framework called Sparkle. This framework doesn’t have a GUI to turn off automatic updates, but it does have and honor a hidden preference. It’s easy and safe to change this setting using the command line (Terminal, iTerm2), so that is how I will demonstrate, but you might be able to use a GUI tool to edit the appropriate preference file if you prefer.

The auto-update feature is controlled by a key named “SUEnableAutomaticChecks” in the Vivaldi preferences. You can check and change the value of this preference using the defaults tool. In your terminal app, type/paste everything after the dollar sign:

$ defaults read -app Vivaldi SUEnableAutomaticChecks

If the value has not been set, the tool will produce this error:

The domain/default pair of (com.vivaldi.Vivaldi, SUEnableAutomaticChecks) does not exist

(which defaults to on).

You can disable auto-update by setting the value to NO:

$ defaults write -app Vivaldi SUEnableAutomaticChecks NO
$ defaults read -app Vivaldi SUEnableAutomaticChecks
NO