my wife is using win11 and I was checking it out from time to time. I didn't notice the taskbar is revertible to the old style, since when is that available and is that builtin or achievable with 3rd party software?
most of my annoyance comes down to the increased telemetry, ads everywhere, and the overall look of the system, dumbing the UI down basically.but I do have concerns of them breaking compatibility with older apps as well.
The task bar is still a bit limited - you can't dock it to the side of the screen, nor can you make it taller, nor (if only shown on one display) can you move it off the primary display.
I've never seen an ad on Windows, and mine came with the laptop - I believe that's because I disable all personalization features when first setting up my laptop. Anyway, the old school bar has been available as a built-in "feature" for probably around a year, you can select "Combine taskbar buttons and hide labels: Never" in the taskbar settings.