How to disable the menu toggler?

I finally decided to set my custom menu block next to the "Branding" block. Instead of inside the "Main menu" region.

Yes, you are right.
This requirement will be completed as you commented if do not want to show the dropdown.
Also, you may remove the main-menu from the region after adding a custom block with images.

innoraftDebdeep → made their first commit to this issue’s fork.

You don't need to disable navbar toggler feature simply don't add your menu block in Header form and Primary Menu Region. It will not convert your menu in toggle button (Hamburger menu).