Youll need to download your photos onto a computet that is on same local network as your umbrel. Then, upload files manually from that computer to umbrel via browser access. Once that is done though, you can set your situation up to automatically send photos to nextcloud going forward. For example, i have nextcloud app on my phone synced with my nextcloud service and all photos i take get uploaded as soon as im home and my phone is back on the local network.

Look into vaultwarden too for password management.