I've been moving my taskbar to the side of the screen for years - it just makes so much more sense on a screen with almost twice the width as height.
Like a stopped clock ubuntu got this one right.
As for aspect ratios, just pick a universal one please, I don't care which I just don't want to listen to my uncle complain about the black bars at the top/bottom when he's watching a movie.
I don't really know the solution for taskbars and the like.
There's sidebars, taskbars, auto-hiding and popups.
I've seen them all done poorly.
I think the worst of all are microsoft products - somehow the online interface for microsoft word is completely different from teams, but they are both uniformly awful.
Strangely I know clearly the ones I hate, but it's hard to recall the ones that work well because they're invisible.
Taking reddit as an example they stack the title and the image above each other then all the links for comments, share, save ... below that. So the entire design is vertical for each post. More than that the trending is at the top and the selector for whether you want hot/new all above it. Even on 1440p I reckon about 40% of the top of my screen goes to tab/url/boomarks and the headers of the page, none of it I care about the moment I want to read that site.
Reddit puts a bit of secondary stuff on the right but nothing on the left of the content at all. The content is literally 25% of the width of the screen, its mostly grey space and yet they have this entirely vertical design for every post and all their controls are at the top. It isn't the only possible way to do this and its terrible for wide screens of any type. The old design utilises widescreens a heck of a lot better which is I presume why it is quite popular.