Unpopular opinion but KDE is a usability nightmare. Mate, Cinnamon or XFCE are much better in this regard.

Actually it is simple and secure. I’ve been using it for 8+ years.

This. Do not expose any service to the internet or even LAN. All clients need to connect via VPN to your machine, no matter if from LAN/home or on the road (WAN/Internet). You can still use a reverse proxy and custom domain names so inside the VPN network everything is HTTPS and each service has a nice domain name.

How often did you need a raw video older than one year?