Screen cracked and processor working slower that a snail

@neilbhor the lagging maybe caused by your display. I prefer to repair the known broken part before assuming that issues that develop after that are new issues. I always consider those firstly to be a result of the damaged part. It maybe causing issues with the firmware and detection or with pulling more amps etc. due to extra heat.

I would replace the display and then re-evaluate. Your Tab M10 (1st gen) is a (TB-X505). Since iFixit does not yet have a guide for this, use something like this video Replacement screens are readily available at many online stores (definitely cheaper than a new tablet).

While you work on your tablet, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has a device with the same issues as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

Repair is War on Entropy!