Hi together,

It is my first post here, and I am also quite new to home automation.

My situation is as follows: I have a synology NAS that i just installed home assistant. So far, everything is working fine (meaning i am just starting to play around with the devices).
now, the tricky part where I am struggling to find information are related to 2 security topics:
1) CCTV: i was planning to build a CCTV using the synology app, which seems quite good. my first impression is that i would be able to access the camera IP and send push messages directly from the synology app on key events. So I am struggling to identify any benefits to have it linked to the home automation itself... since i am new on this topic, i dont know if there are any benefits at all. also, i assume that WIFI cameras would be enough, so no need to look for ZWAVE compatible cameras... any advice?
2) alarm system: i found a lot of door/window/PIR sensors. also i found sirens that i could trigger in case specific events happens. so for this part, i was thinking to just buy all the sensors and build the solution myself. I could set the alarm either with remote control or cell phone, so i dont believe a keypad would be necessary, everything running under z wave. is there any disadvantages to do it? also, is Z wave "secure" enough to trust that the communication between the devices are encrypted, or does it use an transparent system that people could sniffer and read it? seems that the traditional alarm system and the home automation doesn't go along quite nicely if not planned ahead of time. any advice here?