Most changes apply immediately. Anything markedrestart requiredneeds Apply & Reload to take effect.
See the Keyboard Binds / Controller Binds tabs to remap individual buttons.
Click Change, then press a key or mouse button. Escape cancels.
Click Change, then press a controller button/stick direction. Escape cancels. Needs a controller connected and already moved/pressed once (browser requirement before a page can see it).
This is your actual saved config (wolfconfig_mp.cfg) - edit it directly and hit Apply & Reload to save and reboot into it. Re-open Settings to see the latest saved copy.