@AhtishamAshraf (1) If you click my comment to reply, then I would be notified, just as your address to @tlfong01. Otherwise I would only see your comment when I revisit the chat room again. (2) You plan of restarting the script after every RFID read sounds stupid, and would very likely damage Rpi SE's reputation! :)

@AhtishamAshraf (1) Your project is a bit advanced, because it involves three things, RFID, Relay, and Door Lock. I guess only less than 1% of the readers in this Rpi SE and EE SE know what is going on! BTW, our comments in your question section got too long and so the Mod set up a chat room for us, so other readers might us too long winded. Now we have already an answer, I think it is OK for us to comment below my answer, until our comments get too long, and the mod would act again. Cheers.

I have ordered all the relay types , let me share the links for you to check and none of them worked.

amazon.ae/gp/product/B07NF13Q34/…

@tlfong01

@AhtishamAshraf Ah, perhaps I have missed some other important thing. I would suggest a simple test to verify that my guess. (1) What you need is a a LED with a series current limiting resistor to replace the 12V powered lock. (2) Let me first calculate the resistance value of the series resistor. Normally a simple LED will light up if current passing through it is around 10mA. The voltage drop across the resistor when lighted up should be (12V - 0.6V) / 10mA ~= 11V / 20mA ~= 10/10 ~= 1kΩ.

(3) Now you replace the lock by the LED in series with this 1kΩ. (4) And if you now try to use the RFID card to lock the lock (replaced by LED now), the LED would light up. And if you try the RFID card to lock again, ie, second time, without any problem, then the lock is the trouble maker. I have not thought thｏroughly, so never mind if you don't know what I am saying, or just ask me to clarify. Ah, bed time, see you later.