You can create a startup session file: see details here.
If all you want to do is start in a certain folder, the file could be named `~/.config/kitty/kitty-startup.session` and consist of one line:
cd /path/where/I/want/to/start
If you want to make that session the default, in your `kitty.conf` put:
startup_session ~/.config/kitty/kitty-startup.session
You can have multiple session files and load whichever one you want with:
kitty --session /path/to/session/file
Though if all you want to do is start in a new folder, you can just give the folder name as argument as well:
kitty /path/to/folder