CCTV Server using 3 different brands of camera

Hi!, We currently have 3 NVRs for 3 different brands of IP camera with a total of 75CCTVs each NVR has 12TB of storage to save 2-3weeks of videos and we are trying to extend that to at-least 3months.
So my proposal is to create a 60-80TB server that caters all our CCTV camera to easily save data.
Maybe anyone can recommend a solution to have a unified GUI for maybe 75-100CCTV? and a beefy server… Thank you.

Synology support that

Thank you!
Can I setup a TrueNAS as a storage and then a separate server for viewing purposes?

Depends on what camera software you are using.