[BandButcher]

I have used ZoneMinder (https://zoneminder.com/, an open source security cam software) previously for an apartment setup using webcams, but i believe it can work with ip cams, etc. and allows you to save to an external hard drive/ssd/etc...

Wifi im not too sure on, you could try a new cell service but they upcharge on hotspotting... so maybe just regular internet provider or satellite (ex, starlink)

As far as solar, that would likely be your biggest issue... specifically robustness. Solar provides constant energy during the daytime with no obstructions (ex. clouds, shade) but at night time til early morning, power output will be zero (or close to it).

You will need either some type of battery storage or power generator to allow you to have power during solar outages. That is a lot more costly, a couple $1000 at least (inverter or microinverters, charge controllers, batteries, installation costs).

The bright side is you wouldn't need very many panels as the setup shouldn't run you more than 2kW per day (high estimate imo) I'm ballparking that you would need a central computer to run zoneminder (raspberry pi 4/5 or a cheap windows desktop) and the ip cams, wifi router/modem). Those should be able to run on less than 2kWh per day but depends. 6 panels at 350-400W (~200 per, so around $1500 for solar panels but doesn't include install)

I think you could do it all for under 5k (USD), but the internet/wifi most likely will be your biggest fee going forward.