nice website!
mmh the easiest way to have it stay there is to set both of this to "none" like here in lay options:
Screenshot 2024-05-01 at 17.16.44.png
this way u have no transition
other than that its not possible, only if you custom code this navigation:
Screenshot 2024-05-01 at 17.18.10.png
custom code the html and css, put it in "html at top" in lay options -> custom css & html
then use css to only show this navigation on pages you want it to show up on
https://laytheme.com/documentation/custom-css-styling.html#css-based-on-current-page
then u could use page transitions and then it would stay there