I found nextcloud easier to set up than many other services, plus it comes with cloud file storage and other goodies as a bonus.
It is even easy on such obscure platforms as NetBSD in an nvmm-backed qemu virtual machine runnning on a NetBSD host.
(EDIT: well, it wasn't really trivial, the database (PostgreSQL in my case) setup and connection is not necessarily obvious to someone who hasn't done it before, but the fact that it works without real complications on very diverse platforms is a testament to its clean code.)
As to filling up the drives so fast, have you considered transcoding it to a smaller format (such as HEVC/H.265) in real time? I know that would require quite some CPU power. Even H.264 is likely to improve on camera native formats, as those often need to encode the videos with embedded/low-power CPUs. Do you need to retain the footage beyond 3 months?