I also recommend HomeKit video cameras. I have a Logitech Circle View, and it's great.
HomeKit isn't strictly local-only, but all processing must be done locally, and motion events are stored, encrypted in iCloud. Such as any video being stored encrypted to your iCloud account. https://www.imore.com/homekit-secure-video-everything-you-ne...
According to your own preferences, so you would then need to make the effort to have the security settings on your own private cam servers here, so that only those authorized to view, locally or elsewhere, will get anything at all.
In addition you will generally be required to make very specific efforts to set up a "pinhole" in your ISP gateway firewall if you want to allow any non-local access to that stream to begin with. By default broadband ISPs have not intended to make local streams accessible to the web otherwise.
A webcam is plugged into a PC which will need to run some streaming software like today's OBS Studio (or the discontinued Windows Media Encoder, then Expresion Encoder, which were free downloads for earlier versions of Windows). So the PC with the webcam/microphone functions as a simple network media server. You can have your own unique firewall and security settings for this one PC. You will also choose the encoding format for the stream, and the way your authorized viewing workstations will need to be securley logged in, and they will have to have the proper corresponding media codec installed for them to be able to display the stream. Laptops can broadcast this live streaming with no additional hardware.
A netcam will just plug right into your router (or be wireless) and it will contain its own simple secure network media server, so it does not require its own PC with encoding app, to accomplish the equivalent 24/7 streaming. You still need a local or remote computer's media player to view the video stream and a browser to access the netcam's administrative interface.
They're not very stable though. I use shinobi NVR and often one of the cameras stops feeding. Resetting it works but I regret buying them, I have 6 now and they were super cheap otherwise I'd have switched already
I did set up a local SIP server to avoid going out to the internet but don't remember which one now.
https://www.walmart.com/ip/Night-Owl-8-Channel-Bluetooth-DVR...
https://www.bestbuy.com/site/swann-enforcer-8-channel-4-came...
There have been past HN threads where comp software via local lan has been mentioned and sounds really good too - maybe an algolia search HN for reolink (popular hardware for this) will bring up the pertinent threads.
You have to be careful, though — some Chinese companies are known to have been affiliated with making equipment for use in suppressing a Muslim ethic group in China (the Uighur), and they sell equipment under multiple names. We don’t know how much communicating they do to exfiltrate data to their company central facilities.
Daihua and HikVision, are the two main companies I know of to be concerned about, see https://securitycamcenter.com/dahua-oem-list/ and https://securitycamcenter.com/hikvision-oem-list/
Note that companies like Wyze just take hardware from another company (like Daihua) and re-brand them with their own firmware. So you have to be careful to check out who actually makes the underlying hardware.
And with regards to Reolink, I’ve heard they have a lot of hardware problems.
Sadly, this means that to get a reliable network camera from a reliable company (e.g., Axis), you’re probably going to have to spend a lot more money.
Arlo has a solid stance on privacy but is definitely cloud based unless you get one of the older ones with a base station. Their products are also made in china though.
You could also do the whole Raspberry Pi Cam thing.