I think you got plenty of great answers already. Security is not a real concern for a home user. It’s not even for the enterprises. Container escapes are extremely rare and Kubernetes is used very widely among some of the largest companies in the world running thousands of containers.
I think in general people start out in VMs and advance to containers. If you are already using containers stick with it, otherwise you are taking a step back.
Now for why you might want to run proxmox? I do it because I wanted windows, Linux and Jellyfin with hardware decoding on one server.
I’ve tried a lot of self-hosted NVR solutions as well as Synology Surveillance Station and Unifi Protect.
Granted I only tried with third party cameras and never Unifi cameras, but I was not a big fan of Protect, even with latest updates. Performance was just so sluggish for live view to come up or even scrubbing the recording. Support for third party cameras is also extremely limited, only supporting ONVIF and ignoring any events camera provides.
Synology has been rock solid, but very $$$ for camera licenses.
Scrypted to get cameras into HKSV is pretty great. Frigate is awesome at “AI” detection and classification, but needs a GPU or TPU accelerator.
Most recently I decided to save myself some headaches and got Aqara G5 Pro cameras. Native HomeKit Secure Video, ability to save video to NAS just as video files for long term storage, free 24HR continuous recording to Aqara cloud, ONVIF and RTSP feeds so the cameras can integrate with Protect or any other NVR.