Start 11 ( https://www.stardock.com/products/start11/ ) can ungroup the taskbar, but at the cost of making the Start menu / taskbar / systray generally unstable. They are reasonably good at restarting Explorer as needed, but you can definitely tell that something's wrong.
Looks like the dev has moved to Windhawk, and that at least has partial support for ungrouping[^2].
[1]: https://ramensoftware.com/7-taskbar-tweaker-and-a-first-look...
[2]: https://ramensoftware.com/windhawk-mods-for-the-windows-11-t...