If you are running Windows 11 Insider build 22616 then you would need to do the following if you want to use the enhanced taskbar features with Start11 1.22 : 

Open regedit and navigate to the following registry key.

HKEY_CURRENT_USER\SOFTWARE\Stardock\Start8\Start8.ini\Start8

Create a new string value with the Name "OldTaskbarOn11" and give it a value of 1

Then sign out and in again.

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Please note that there is a possible issue with secondary taskbars in that build but this is addressed internally - see below.

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We should have a beta update next week which as part of a series of fixes for other issues also addresses this without any changes needed and also resolves a flickering issue the taskbar has gained in the newer build due to OS changes.

The good news is the Microsoft changes mean transparency, blur and texture control will be returning to Start11 on that build.

I should repeat that unless you have need to be on a beta/dev channel version of Windows 11 that you do not run it on a machine you use on a regular basis.  Also you have a small window to move off dev channel onto beta channel so unless you really need to be on dev it might be wise to change your channel to beta.  Dev channel builds are likely to become even less stable going forwards.