GB wrote:

These Sonoff switches are tiny, and the terminals are stupidly small.
I'm more concerned, though, that the whole thing has a clip on plastic
cover. If this falls off, the terminals are exposed.

Should I just return them as unsafe?Â* If I do, does anyone have
recommendations for some switches that are a bit better made?

https://www.amazon.co.uk/gp/product/B07WFM246Q

The Shelley devices seem better designed to fit inside a backbox

https://shop.shelly.cloud/shelly-1-wifi-smart-home-automation#50