I will try turning off the collision detection

You may have it set to “Early” (or something like that), which is very / over aggressive. I very occasionally get “corrective steering” alert on narrow country roads, but that is without any oncoming traffic, just the narrowness of the road / markings / verge / whatever looking like a possible threat. (I live in a rural area of narrow roads, so even given that “it aint often” in my case)

My last couple of cars have both had this ability

Curious to know what they are, as I thought that was somewhat uncommon – perhaps they were high-end models?

As far as I know it is database only (my car with FSD seems to be accurate, but maybe the database for speed limits around here has good quality data)

‘ve only had my Model Y a couple of days

There is a slim chance that your car has stale map data (almost certainly it will have stale system software, if so that will update, potentially multiple times, over the coming days – parking the car where it has WiFi will help with that) – that won’t get you sign-reading! but it might get you a more recent version of the map data.

I am reasonably sure that mine (FSD) recognised temporary speed limits (road works type ones) at some point, but it certainly doesn’t at present, so either my faulty memory, or an update that shouldn’t-have-been [e.g. not approved for UK] and was subsequently removed.

I expect it is entirely possible that will be fixed by OTA update at some point in your ownership (although quite possibly only if you have EAP or FSD). No consolation, but probably some feel-good if and when it happens