MileStone Essential+ is great video surveillance software which support 8 cams for free and it’s design to expand to more with paid versions.
I use it at home with 4 cameras and new version 2019 R2 enforce a new level of security to use trusted certificates and deprecate old self-signed certificate which most mobile OSes refuse to verify.
Easiest way to generate it is via CertifyTheWeb which will generate a free SSL certificate for 3 months and you can renew it for free.
I used Azure DNS validation to confirm I own the website and publish it automatically on my local ISS website.
To get a public website, you can use my.dot.tk