I currently use both "Opera Browser" and "Opera GX Browser" on one computer in different ways, and, because I use in different ways, there form some variations in bookmarks, settings, passwords, cookies and so on, between those two browsers. For example there are more bookmarks in "GX Browser" than in "Opera Browser".
I want to synchronise my "Opera GX Browser" only, because there are more important data in it and I am likely to change my device soon. However, if I use the same Opera account to sync "GX Browser" as the Opera account I had used to sync the normal "Opera Browser" before, will the bookmarks and settings in "GX Browser" be replaced with those in the normal "Opera Browser"?

Also, a simple question, what happens to existing bookmarks, settings, passwords and cookies in the normal "Opera Browser" after you sync it?
I'm asking this question because I have a traumatic experience where I lost all settings and bookmarks by syncing Google Chrome.

Any opinions and ideas are welcome. Waiting to hear kind voices.