I just tried it out, not even knowing before your comment.

Right click taskbar, uncheck Lock all Taskbars, click and drag it to the left side. Done.

Meanwhile, when I was using my Steam Deck as a desktop, it refused to save the position of my taskbar on my main monitor. Plus, when I did move it across each time I booted up, it would leave behind half the buttons because they’re considered separate entities. Thank god for oh almighty user customization - making it incredibly hard to do something simple.