I don’t know any specific desktop applications, but you could try libre office calc :D
Due to the nature if those charts, they’re usually web based, not desktop native, and will probably have to be self hosted, even just locally. For example, Redmine supports Gantt charts and can be spun up fairly easily from its Docker image.

What about Mermaid? mermaid.js.org/syntax/gantt.html

It supports Gantt charts and has a pretty nice language for modifying chart content once you get used to it.

I use Obsidian with the Mermaid plugin for offline work, but there are tons of good web-based options out there, too.

Mermaid

Create diagrams and visualizations using text and code.

PlantUML supports Gantt charts if I remember correctly. Can run locally (java if I’m not mistaken) or via web.
Planner does Gantt cuarta.
I used OpenProject before. Mainly for easy collaboration through the web though, I don’t think it offers a native version.
You could use ProjectLibre although it might be overkill
#1 Alternative to Microsoft Project Free Project Management Software & Open Source | Projectlibre

Yeah, it’s overkill, and also breaks on anything newer than java 11 or 12

I used planner recently wiki.gnome.org/action/show/Apps/Planner?action=sh…

I also searched a lot z and didn’t find good options. It works, but I don’t like the way it looked.

Apps/Planner - GNOME Wiki!

Why a gantt chart for a road trip though. There are not that many parallel things you usually do, no?
yeah its overkill. any kind of timeline software would work.
Libre office calc would do the trick also, every cell is a day for example
www.ganttproject.biz This one is nice
GanttProject: free project management tool for Windows, macOS and Linux

Download GanttProject for Windows, Linux and macOS

GanttProject
calligra plan has this iirc