GSM door/window sensor with SIM card - ready-made models without control unit?

Door opening and closing sensor I am looking for a finished product or a product realised by someone as a hobbyist based on the GSM network with the possibility of inserting a SIM card without additional control panels.

My assumption is that I would like to purchase a device along the lines of "TUYA WIFI WINDOW OPEN DOOR SENSOR" link: https://www.idomtuya.pl/pl/p/CZUJNIK-SENSOR-OTWORZONYCH-DRZWI-OKNA-TUYA-WIFI/44 based on GSM, not Wi-Fi, giving notifications to the phone in the form of SMS or notifications in the app. Is there a device or do you know of something to recommend?

The second topic is a sensor: TUYA SMART LIFE WIFI PIR motion sensor operating on GSM, not Wi-Fi.
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And how do you see powering this? Because GSM for network connectivity takes a bit. Unless you don't care about notification speed, it could be switched off and only log on after an event.
All those wi-fi things work for a dozen metres, hence they last a long time on batteries, and GSM has to be able to go further.
Why not a PBX? Do you think it will be cheaper without it?