I would go down to 15 fps to save on the bitrate
Recording h264 with a 3.7MP bitrate will fill your 5TB system in a matter of hours. About 20 hours in your case approximately.
Reolink cams have a 640x480 "fluent mode" as they call which can be used for continuous recording. With your current setup I cannot see any way out of the 480p continuous recording.
BI can also make use of your GPU for video decoding in particular, this will save precious CPU cycle that could be used for running detection algorithms.
Concerning the Windows system is concerned, you must debloat it. Sophia debloating script is continuously updated and will let you achieve a clean system easily.
The Cisco switch will give you the final verdict concerning your networking usage. A few show interfaces type number will let you know in detail of the current status of each port. If needed, running an etherchannel on both 1Gbps links should answer the bw needs.
It seems that Windows 10 pro support link aggregation via a feature called 'Network Teaming'. Feel free to experiment here and let us know
Finally your switch supports QOS, which is a killer honestly. Here you'll mark frames (802.1p CoS) depending on the kinds of critical traffic your network is running.
The CoS markings are explained here
QoS Configuration through CoS Trust Mode on 200/300 Series Managed Switches
The egress queue congestion management
tools are explained here
Configuration of Quality of Service (QoS) Queue on 200/300 Series Managed Switches
With this you got all the tools, needed to have a crystal clear setup
Good luck