Uk gsm query on mobile type and plan type

I am in UK. I have 3 cams on protect plus plan. If I buy the alarm does this mean I do not need pay any more monthly ? I want to use GSM backup so is this available in UK and do ring provide sims ? Also need clarification that gen2 is lte ( 4g ) compliant as 2g is defunct in uk 2025.

I have the alarm system, internal stick up camera and an outdoor wired camera along with a doorbell and all is covered with the protect plus for £8 a month.
The SIM is already in the alarm hub and connects to any mobile network like a SMART meter does. All works fine here.