SUMMARY
android phones need some sort of backup. Currently, people often use google services or other cloud to backup contacts, messages, apps, calendar, bookmarks and call logs but there are android apps that let you do that offline on the phone itself.
https://play.google.com/store/apps/details?id=com.idea.backup.smscontacts&hl=en_US

This free app for example lets you schedule all types of backups. Now, i have used this app and been using kde connect extensively for the last 2 years and i have set up a janky procedure where i use this app to schedule backups to a folder and then use syncthing to backup that folder to my desktop linux. Its taxing because it uses lots of components. 
I am suggesting kde connect have this functionality such that i can set up for example, kde connect to every week backup my contacts to a folder on my desktop and kdeconnect should do it automatically.