The camera licenses are a given... but servers and storage devices aren't the clearest outline for their requirements...
My provisional preferences (if affordable) is Milestone - Professional+ because if I'm not mistaken - you can select a box, and it'll create a history of events in that box, yes?
• Single Server
• Affordable QNAP
First, some of the IP cameras I either own or am interested in seem arbitrarily to have H.265 ignored despite the cameras inclusion of H.265+ Milestone as of yet doesn't acknowledge or support it, but maybe it will soon, along with many more units manufactured by QNAP.
The "certified" QNAP product is $7,000, diskless.
(Your only choice is whether you want SAS configuration or not.)
When I read the hardware configurations of the Milestone equipment and look at the BOM, there is absolutely nothing special looking about the hardware except the costs.