Help me design / build a BI server and cams

I am an IT Tech for a smaller municipality and we are wanting to replace our current public safety facility 8 yr old ExaqVision camera system with BI. Can you help me with specs on a pre-built server and cams to fit our needs. Here is some info and specs I know of

20 cameras total. 17 outdoor cameras (I am thinking turret in most areas as to help with spider webs?)
3 cameras need to be small for corner / secure mounting in a holding cell area (Hikvision’s DS-2CD6W45G0-IVS 4 MP Corner-Mounted ?)
most outdoor cams will only need to cover building entrances. A few will be in parking lots with 20 yards being the longest view.
60 day min. retention needed
record only on motion
live view monitoring 24/7 from 2 different PC's in the same network / facility
rack mount server
multiple NICS in server
will be all on VLAN network with Gb switches LAG ports
$20K is our budgeted amount
reliability, redundancy and high endurance are the primary goals.
not a huge need for video review (2-3 times a yr is all we have requests for now)
Some AI like people counting in entrances for now
Might have need for license and facial recognition AI later
 
I am an IT Tech for a smaller municipality and we are wanting to replace our current public safety facility 8 yr old ExaqVision camera system with BI. Can you help me with specs on a pre-built server and cams to fit our needs. Here is some info and specs I know of

20 cameras total. 17 outdoor cameras (I am thinking turret in most areas as to help with spider webs?)
3 cameras need to be small for corner / secure mounting in a holding cell area (Hikvision’s DS-2CD6W45G0-IVS 4 MP Corner-Mounted ?)
most outdoor cams will only need to cover building entrances. A few will be in parking lots with 20 yards being the longest view.
60 day min. retention needed
record only on motion
live view monitoring 24/7 from 2 different PC's in the same network / facility
rack mount server
multiple NICS in server
will be all on VLAN network with Gb switches LAG ports
$20K is our budgeted amount
reliability, redundancy and high endurance are the primary goals.
not a huge need for video review (2-3 times a yr is all we have requests for now)
Some AI like people counting in entrances for now
Might have need for license and facial recognition AI later
You have a decent budget and in your particular case being used for a municipality You should be using a commercial VMS. Take a look at digital watchdog IPVMS which is nx witness rebranded for the North American market... Licensing is about 80 to $90 a camera. However the licensing includes free lifetime upgrades.
If you are in the US you are likely not permitted to use hik cameras for your municipal use.