There’s a pretty cool write up by KittenLabs about their SolarCamPi project - it’s pretty involved as far as DIY projects though, even down to stripping features out of the Raspberry Pi so it would use as little power as possible..

Awhile back I dabbled with a timelapse setup where I had a battery, GoPro and a Raspberry Pi with a 4G hat for remote monitoring - but that was never intended to run 24/7. I just set those up and accepted that they’d run for as long as they ran and then collect them.

Lots of 4G/WiFi solar security cameras around as another sort of ‘all in one’ solution - typically the main issue is they all want you to use their app. If you can find one with rtsp or ONVIF it’s easier to make them work with whatever you want.