Misbehaving touch controls

I've recently started playing on my Lenovo Tab3 7 device, after playing for a while on my iPad 2 (which is seriously old and lagging a lot with recent updates). My Lenovo doesn't lag, but it doesn't have the smooth touch controls which the iPad had.

Now it has serious problems detecting long pushes, as when trying to eat or mine or even move the camera.

Most often if I long press it doesn't register it at all, and it places a block instead of starting to mine (or eat).

In quite a few cases, it starts building the mining circle animations, but somewhere before completing the mining of the current block it resets and starts over (or places a block).

This seems to happen more often when trying to mine directly in front of me on blocks close by. If the distance is >2 blocks, and off center, it seems to mine slightly more reliably.

The glitching long press occurs on both realms and single player worlds. I've cleaned my screen thoroughly to avoid misdetection of pressing, and I've only used one finger to do the press carefully avoiding to have any pressures elsewhere on the device so as not to create accidental touches (aka no other fingers or palms have touched the front of the device).

Minecraft have been the only app running on the device, and it was recently power cycled.