Surveillance Station alternatives

Due to Synology's recent decision to remove support for the H265 codec, I am looking for an alternative to Surveillance Station.

Since I am otherwise satisfied with the NAS (file sharing, photo storage, etc.), I was thinking of dedicating a second machine (e.g., a NUC) solely to managing security cameras. I'm looking for something non-intrusive and simple enough for other family members to use.

I've read about software like iSpyConnect, ZoneMinder, etc. I enjoy tinkering, so DIY doesn't scare me, but I really don't know where to start. Do you have any suggestions?