Unfortunately, it appears that in the current Paraglider-forge-20.1.1.jar, stamina is entirely broken. It works as intended when paragliding, but I cannot get it to deplete from running/swimming even on a clean install with no other mods and no changes to the default config.

I tried reloading the config with the /paraglider reloadPlayerStates command that was listed in the paraglider-player-states file, but that command supposedly doesn't exist in the current version of the mod according to minecraft's console.

Did you try enabling runningAndSwimmingConsumesStamina option in paraglider-server.toml config file?