This is still a problem in June 2022. I’m probably going to have to switch distros over it.
I have a 16:9 1080p panel and a 21:9 2560x1080 panel (just the 2 panels total.) I have them stacked on my desk with the ultra-wide on top and the 16:9 on the bottom.
I simply cannnot maximize any window on the top display, the maximize button does literally nothing and windows snap to a weird half-line on the screen that doesn’t line up with anything when you move them around. It’s way beyond “I can just drag window corners to work this out.”
This is just not an acceptable behavior in a shipping OS.
This sounds like a resolvable issue assuming someone who can tweak code has a similar setup and hardware as you. Please raise an issue upstream - and if you yourself can pitchin then even better!
On your top monitor, put the panel on top.
On your bottom monitor, put the panel on bottom.
Position your monitors accordingly in parameters / displays ¡ important !
And maybe switch between your monitors as primary screen to see which one fits better in this « role ».
I’d say bottom monitor as primary.
But yes, it’s just beyond understanding how bad Budgie Desktop panels behave with multi monitors ( or laptop + external screen, it’s the same and it’s not a rare use case. )
For the moment, see panels as walls, final borders, which orientation is determined by the relative position of a screen before or after that wall.