We use these … link below
problem using separate supplies one Poe for cameras and one to power nvr or pc …. It can take a long time for startup plus nothing for router for alerts
these are good …. Just plug Poe nvr into it …. Less to fail plus you can power your router
https://1va.co.uk/entry-level-ups-systems-c-1.html?ceid=f446905c28def4ea070ec45e2720af20