Hi Maurizio,
I can’t say for sure without installing the theme here. But it looks like it should be OK.
You may need to remove some residual styling:
https://www.maxmegamenu.com/documentation/faqs/removing-residual-styling/
The best thing to do would be to install the plugin and see what happens, you can always uninstall it and it will go back to your default theme menu.
Regards,
Tom