For a "complete" search in the OpenStreetMap-data I suggest [Overpass Turbo](https://wiki.openstreetmap.org/wiki/Overpass_turbo).

In this specific case I'd take a little detour over taginfo (https://wiki.openstreetmap.org/wiki/Taginfo), e.g. search for `surveillance` (https://taginfo.openstreetmap.org/search?q=surveillance) there. A little bit of clicking (Type > Values > ALPR) leads to https://taginfo.openstreetmap.org/tags/surveillance%3Atype=A... If you click on 'Overpass turbo' on the top right, you get to a pre-filled search on Overpass turbo. Scroll the map to the region you want to search (start small), and click 'Run' on the top left.

Voila.

However, even ALPR doesn't show any devices for me:

I'm glad citizens in the EU are more on top of this. I really wish we as USA citizens had access to the same database of GPS coordinates for each Blink, Ring, and Amazon Key device that police do. Does anyone know how/if something like that could be FOIA'd? This seems it would be particularly fruitful if FBI/DHS has a comprehensive dataset for the entire nation.

Though I do worry that they may not "have" the dataset, but rather just have "access" to it via a queryable Amazon/Palantir database/API.

I've panned the map over several parts of the US, and see many ALPRs mapped in OpenStreetMap. You can also use the 'Wizard' of Overpass turbo, and enter ""surveillance:type"=ALPR around Miami" (or any other city (e.g. your home town), with quotation marks around surveillance:type) and increase the `radius` in the query until you'll find some. As an example, here are the ALPRs 25km around Miami: https://overpass-turbo.eu/s/2dVP