Hi,
Try the following and check if the problem is resolved:
i). [https://www.hardreset.info/devices/lenovo/lenovo-tab-m10/wipe-cache/|Wipe the cache partition] and check if it works OK.
ii). Start the tablet in [https://www.hardreset.info/devices/lenovo/lenovo-tab-m10/safe-mode/|safe mode] and check if it works OK.
If it works OK when in safe mode, then a ''downloaded'' app is the cause of the problem. The trick is to find out which one it is. You will need to uninstall each ''downloaded'' app, one by one and test the tablet in normal mode between each uninstall to see if it works OK. When it does then the last ''downloaded'' app that was uninstalled was the culprit. A ''downloaded'' app is one that you downloaded and installed in the tablet and was not already pre-installed when you got it.