After doing a research to disable the search bar on the main menu, I found several pages (most of them old ones) with some workarounds but nothing solid that will do the job.

The most recent link I found is this one:
https://forums.linuxmint.com/viewtopic.php?t=351487

In my case I have a multimedia center running Linux Mint 22.1 and every time I click on the Menu, it shows the keyboard on screen (because I set it like that to use only the pointer/mouse). I don't have a keyboard and that is the main reason. But what a surprise when I also installed Linux Mint on my Dell YOGA (touchscreen) and after I set it up as a tablet, I found the same problem! Every time I open the menu the focus goes to the search bar (something that is right to focus first the input field) but because I don't want to search any app, it is becoming quite annoying.

The link I shared pointing to the linuxmint.org forum explains exactly the same UX problem, and adding an option in the configuration menu (Layout and content) to switch off or hide it will be very handful for users in these situations.