Hi,
I face the same issue on my Huawei P30 Lite, and it is very annoying.
I tried changing the screen resolution as @mib2berlin and @jstressman mentioned. It didn't work ( I have 3 screen resolutions: smart, high, and low, the annoying weird bottom bar on top of the status bar stays in all of them).
I tried to activate and deactivate the address bar at bottom (my address bar is usually on top) as @ipan12 suggested: when the address bar is at the bottom, the annoying bar disappears, and actually, I think I might like having the address bar at the bottom, so I'll give it a try.
However, when deactivating the bottom address bar, the annoying bar reappears.
So the problem is still there.
To reproduce the issue, I have a Huawei P30 Lite, running on Android 12.
I hope that it will help the Vivaldi team to solve the bug.