With regards to the search issue, that surprises me as whilst Start10 had a problem with loss of keystrokes, Start11 changed things to avoid that and we have not had further reports of this. If you only want the no search look you can hide the search field and keep the Start11 search.
I'm also experiencing this on Windows 11 (I specifically noticed it in the Windows 11 style). I have the "Use Start11 search in the Start11 start menu" option turned off and the "Hide search box unless searching" option on. Often when I begin searching after clicking the start button, the first letter can get left out. If I perform a search, click on the taskbar, then click on the Windows button to do a search again, nothing happens the second time. I need to click somewhere else first (on an open app, or on an icon that opens an app) before I can search again.
Another problem I'm having is that I can't pin new items to the start menu in any style in Start11, and if I unpin something, I can't get it back. Pinning works fine in the native start menu, but pinned items aren't working for me in Start11.
Finally, there's a large gap (blank space) between the pinned items I do see and the bottom of the start menu (in Windows 11 style). This is a gap within the start menu (not a gap between the start menu and the taskbar), and it would be nice if Start11 removed that extra space and only opened the start menu as tall as the amount of apps you have pinned.