You can also configure it to keep open window buttons separate from the launcher icons, but with the lack of double stacking I rather have it "take over" the launcher.
The way I've set it up it will also only show the open windows for the virtual desktop or screen the bar being shown at, which helps alleviate the crowding issue of only having one row.
> I'll also create a feature request for resizing/stacking of rows.
That's the spirit! Please do file feature requests with the docks that you think might be close to what you want. A lot of foss projects are pretty receptive to feature requests.
Keep in mind that in the foss world you're not a customer - the people doing the work will be donating their free time to build a feature you're asking for, so please be nice and polite to them - the worst thing you can do on a feature request is have an entitled tone, or insinuate that their software is crap because it doesn't quite do what you want :)
Someone else suggested that adding 2 xfce panels might accomplish something pretty close to what you're after. I had a bit of a play around and agree with that. I didn't replicate your request exactly (because my panel is very different and I didn't want to break my setup too much) but depending on where your priorities lie I think you could probably get something pretty close.
Options that are similar:
a) If you really want the 'start menu' button to span both rows, use a single panel and set "row size" to e.g 48px and "number of rows" to 2. The con of this method is that the task list (list of programs) will span both rows, which is not what you have.
b) If you want to replicate your preferred setup more closely, you might not be able to have the 'start menu' button span both rows. To accomplish this I would add 2 panels of e.g 24px and put them both at the bottom of the screen. In one you'll have the task list and in another you'll have icons.
The media player controls might be an issue in xfce. I'm not sure if anything like that exists. However you definitely can have a systray icon for your media player which pops up media controls when you click on it.
There are other docks with more customisable widgets that will give you media controls like those, but I can't really make a solid recommendation for you unfortunately. The one I used to use was called cairo-dock, but I think that might be dead. Before that I used one called avant-window-navigator. There's also a couple of others that I'm aware of, e.g tint2 and wbar.
I'd be a little bit surprised if there are zero docks out there that can do what you want. The thing is you might have to try screwing around with the config for 20 different ones if you insist on replicating that layout exactly :/
https://github.com/home-sweet-gnome/dash-to-panel
It's a very configurable extension for gnome that can do all you described except double stacking...
I've uploaded a video demo and a config file that makes it kinda like what you want, again no double stacking:
https://github.com/amlib/dash-to-panel-config/tree/main
You can also configure it to keep open window buttons separate from the launcher icons, but with the lack of double stacking I rather have it "take over" the launcher.
The way I've set it up it will also only show the open windows for the virtual desktop or screen the bar being shown at, which helps alleviate the crowding issue of only having one row.