Domoticz

Now that the bbq season is upon us, I need to stop my "smart" home locking me out on the patio at night with guests. Watching the stampede to the patio door is quite funny but... . So would appreciate a recommendation for a battery operated sensor. I can see that there are quite a few brands available and some of them seem incredibly cheap but are they any good? ...

I recently purchased on of these

https://a.aliexpress.com/_EGs7VM3

But it's not great, it is cheap though.

Only send 'on' not off. But you can set auto off or work with last.update.

Realise that 433 sensors normally don't have a guaranteed delivery like zwave or zigbee so you may have to jump up/down a bit more. It should work fine for your purpose but using these has limitations (e.g. alarm systems).

Take care that, if anyone (or anything/animals, some spiders manage to trigger PIRs sometimes even if they are not supposed to be seen as a moving hot spot) moving in your patio, this'll prevent lock!
This may not be what you expect or should be coupled with some other presence information to have "stay open" being conditional upon you/relatives presence at home.

So everyone seems to have reservations about using these. What the best recommended practice then?

Why is your smart lock locking the door automatically? If triggered from Domoticz you could make a party switch in Domoticz that overrules the normal locking.