Screensaver and iPhone Mirroring (Bug/me being dumb?)

Looking for some assistance, I've recently updated all my gadgets to the latest OS Versions. Set a new screensaver (Macintosh, it is gorgeous if you haven't seen it yet!) but now I can't disable 'Require password after screen saver begins or display is turned off'. My device is in a private office and I have no need for a password on it, so I'd like to disable that, but I can't... I followed settings on the iPhone to disable iPhone Mirroring (I think) but it still greys out the option to change from immediately on MacOs (Lock Screen section). Anybody know how to fix this? I don't need/want to use iPhone mirroring anyway, genuinely don't see the point, so what gives?